Isuzu 3.0 lacking power / tourque

Submitted: Wednesday, Sep 05, 2018 at 16:04
ThreadID: 137201 Views:1896 Replies:16 FollowUps:22
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I have a 2014 Isuzu that has done 114000k (3000 since I have owned it) and it has been going fine until I started towing the camper trailer (about1.5 - 2 tonne).
It just lacks the power on hills. Without the towing, I have not had any problems to date. What temp. should the intercooler normally operate at and If I had a Flashlube Catch can Pro fitted and the manifold cleaned out, would this assist ?
About ready for my next trip and may have to stay in flat country if unable to find a remedy in time. At this stage I am not ready to spend big bucks on exhaust or new chip/programing.
Scratcher
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Reply By: Kazza055 - Wednesday, Sep 05, 2018 at 16:55

Wednesday, Sep 05, 2018 at 16:55
We have a 2014 D-Max towing a 2500kg van. Considering our van weighs the same as the car I don't expect to be able to climb hills as if it wasn't towing, after all it is only 3L motor.

I doubt you will gain much at all by upgrading the exhaust as it is already 2.75", the few reports I have read have achieved next to nothing and the owner had regretted spending the money doing it.

There are a few that have done the ECU upgrade are more than happy with it but I wonder what that improved performance does to the renowned longevity of the Isuzu.

Maybe you just need to slow down a bit and smell the roses. I have done some very steep climbs with the van on the back and to me it does what I need it to do. On very steep climbs I tend to put the box into manual so I can anticipate what is coming up and move down to a lower gear way before the auto would.

I have considered doing the ECU upgrade using ECU West but I can buy a lot of fuel with that money.

If I have wanted something with more grunt I would have brought an F truck or something similar.
AnswerID: 621030

Reply By: Jackolux - Wednesday, Sep 05, 2018 at 17:10

Wednesday, Sep 05, 2018 at 17:10
I had a 14 Dmax from new and towed a Tvan camper , I would say power was adequate certainly no power house , it would slow do on hills any hill , that's to be expected it is only a 3lt Diesel with 380nm and 130kw .
It's impossible to say if yours is down on power without driving it ,
Cleaning the intake might be worth a try ,
Intercooler temps I have no idea , it would depend on ambient temp

AnswerID: 621031

Follow Up By: Member - Scratcher - Wednesday, Sep 05, 2018 at 17:32

Wednesday, Sep 05, 2018 at 17:32
Thanks for the follow up Kazza and Jacko, Maybe I was just spoilt with the 2012 Ranger that I had (3.0L, 115Kw & 380Nm) which pulled the same trailer up Mt Hotham (and at times hit forth gear) and could not be faulted. Wish I still had the Ranger but it came to a sudden end when a car pulled out from a side road and I could not avoid a T Bone job.
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Reply By: swampy - Wednesday, Sep 05, 2018 at 17:38

Wednesday, Sep 05, 2018 at 17:38
HI
If auto select a gear manually.
Yes its only a 3ltr!! Under 400nmtq Closer to 600Nm would make a difference but the motor maynot last.
A dual cab 4wd tub body is around 450kg heavier than a 2wd single cab variant .

AnswerID: 621032

Reply By: Shaker - Wednesday, Sep 05, 2018 at 19:56

Wednesday, Sep 05, 2018 at 19:56
I had exactly the same problem with a Discovery 2 a few years ago, it turned out to be soft intercooler hoses, replaced them with silicone hoses, instant fix!

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Follow Up By: RMD - Wednesday, Sep 05, 2018 at 20:17

Wednesday, Sep 05, 2018 at 20:17
Soft intercooler hose cannot keep expanding to absorb the infinite airflow from the turbo and is completely wrong as far as constant power is concerned. Just not possible. Something else must have been the low power problem.
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Follow Up By: Shaker - Wednesday, Sep 05, 2018 at 21:39

Wednesday, Sep 05, 2018 at 21:39
It wasn’t something else, or I wouldn’t have said that new hoses fixed the problem.
Spend a bit of time on the AULRO forum & you will learn something.
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Follow Up By: Nomadic Navara - Thursday, Sep 06, 2018 at 09:31

Thursday, Sep 06, 2018 at 09:31
"Soft intercooler hose cannot keep expanding to absorb the infinite airflow from the turbo "
Is it the hose before or after the turbo that causes the problem?
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Follow Up By: Rangiephil - Thursday, Sep 06, 2018 at 20:57

Thursday, Sep 06, 2018 at 20:57
The problem is that the hoses separate internally and when under boost the internal part of the hose closes sometimes fully.
The hoses in question are from the turbo to intercooler or intercooler to inlet manifold.Easily and cheaply replaced with silicon for about $100.
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Follow Up By: Shaker - Thursday, Sep 06, 2018 at 21:26

Thursday, Sep 06, 2018 at 21:26
Exactly, much like a cholesterol blocked artery.
After being told it couldn't have just been the hoses, I wasn't going to explain!
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Reply By: RMD - Wednesday, Sep 05, 2018 at 20:13

Wednesday, Sep 05, 2018 at 20:13
Scratcher
I hope you are allowing for the load you are towing in the performance comment.
If suddenly towing you will be asking for more power and that creates more heat
Perhaps the EGR valve is stuck or partially open because of the common contamination experience after similar km distance travelled. Perhaps have it checked before thinking of performance gear or mods.
If the EGR valve is stuck or gummed, it may be because of the oil quality you use in the sump. Many, many oils available are not good performers at all. If it isn’t a low ash oil or synthetic then the likelyhood of EGR problems is increased. Quality oil seals better and therefore less piston ring blow by, less blowby of contaminants means cleaner oil for longer and less oil fumes to cause problems in an EGR valve or intake manifold.
If your manifold is not heavily reduced in size internally then there should be no problem with the manifold. That does not mean it is excluded from the issue though.
Asking what temp the intercooler runs at, indicates you have a limited knowledge of an item which varies in temp and intake airflow cooling temp as it operates. There is no temp reading for them, it all depends on turbo boost, intake air temp, ambient airflow through the IC fins and much more. You have no control over it anyway.

Fitting a catch can can only do something into the future, the current problem cannot be fixed with a catch can. Unless you understand what they do and how it operates, suddenly fitting one is useless.

Do you know for sure you have no turbo hose/intercooler pressure side air leaks before considering other actions?
Is the air cleaner actually clean and free flowing to provide a good airflow for the expected increase of turbo flow demand while under the increased load?
Have you ever had the airflow meter cleaned so the unit senses intake air temp and airflow rate correctly, so it regulates the boost and fuel injection of the ECU for best power and performance. Cleaning the boost sensor which is just before the throttle body may also be a good idea.

At 114000km has the engine intake and exhaust valves EVER been adjusted. Many dealers DO NOT, adjust them when they should be done, ie, every 40000km. Your engine may never have been done and although sort of ok for normal use, when the demands of intimate airflow of intake and exhaust gas flow WILL BE diminished under the demands for more power under load which is different to empty cruising.
Reduced clearances of engine valves CANNOT BE HEARD and if wrong the air flows and exhaust will not be in sync with each other for proper operation. Just because a service book says it has been done means absolutely zilch.

Get your engine correct in every way before ever thinking of performance chips or programming. Doing that would ensure an engine failure as additional stresses would be introduced and the engine unable to repond.
AnswerID: 621037

Follow Up By: Nutta - Wednesday, Sep 05, 2018 at 20:49

Wednesday, Sep 05, 2018 at 20:49
Something else must be up, hard to imagine an engine with those sort of kay having issues, they are a pretty bullet proof motor.

Has it been like this since new?

When i bought a ranger i took a isuzu for a spin and it didn't have much grunt (i thought). Not a bad engine regardless.
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Follow Up By: Member - Scratcher - Wednesday, Sep 05, 2018 at 23:00

Wednesday, Sep 05, 2018 at 23:00
Thanks RMD,
You are correct, I know nothing about intercooler temps, but was once told that the air flow for its cooling is critical and must not be reduced by blocking grill area with large light bars etc. The catch can suggestion was for future benefits.
The Isuzu has a manual box. Will be taking vehicle in for a service soon to have the 120000k service. Will be getting the air hoses etc checked then.

Scratcher
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Reply By: KevinE - Wednesday, Sep 05, 2018 at 21:46

Wednesday, Sep 05, 2018 at 21:46
Seeing as nobody else has asked; is your Isuzu an auto, or a manual?

If it's an auto; do you know how to use the sports shift & have you been using it while towing?

If not, therein lies your problem.

AnswerID: 621042

Reply By: Member - cruza25 - Thursday, Sep 06, 2018 at 08:22

Thursday, Sep 06, 2018 at 08:22
Start with the very basics.

Have a good mechanic do a thorough service

At your kms

1. New air filter
2. Clean maf sensor
3 dismantle and clean egr system and check egr is functionally ok
Plus the normal things like oils filters and physical check and adjust the valves, check intercooler pipes.

Then fit a munji cable after you have read the benefits

Also maybe worth remove intercooler to clean external fins and flush the inside clean of any oil.

Cheers
Mike
AnswerID: 621049

Reply By: Member - Scratcher - Thursday, Sep 06, 2018 at 11:05

Thursday, Sep 06, 2018 at 11:05
Thanks cruza, but what is a munji cable about?
Will be seeing the mechanic today.

Scratcher
AnswerID: 621052

Follow Up By: Member - cruza25 - Thursday, Sep 06, 2018 at 12:24

Thursday, Sep 06, 2018 at 12:24
It will partially or completely disable the egr.
To stop the engine ingesting it’s own poo.
The egr feeds hot exhaust gas and abrasive soot back into the inlet manifold then through the cylinders turbo etc.
It’s to reduce pollution to meet euro 4 standards. But just wrecks the engine, makes the oil dirty and clogs the intake with a build up of black sludge.
The munji cable disables the egr valve to stop the flow. You need to do a clean first as you will have quite a build up after 115000 kms or so.
Some will say off road use only or that you are going to be responsible for global warming but it will save your engine.

https://munji.com.au/collections/isuzu-d-max-2012-current/products/4jj1-common-rail-egr-delete-kit?variant=11797986177
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Reply By: Member - McLaren3030 - Thursday, Sep 06, 2018 at 11:51

Thursday, Sep 06, 2018 at 11:51
Hi Scratcher, a lot of suggestions given by others. I do not own an Isuzu, but have read extensively with regard to Exhaust upgrades, ECU remapping & performance chips. Depending on which Diesel Mechanic/Performance centre you talk to, they will give you various reasons why a Performance Chip is better than an ECU remap & vice versa, but one thing they all agree on is that an exhaust upgrade to at least 3" is one of the most cost effective performance increase you can do.

Depending on your location, there are a number of different Exhaust specialist that will supply &/or fit an exhaust system to your car. One thing to look for with an exhaust system is to have one that has been "mandrel bent", this ensures there are no kinks or narrowing of the internal diameter of the pipe during the manufacturing process.

Understand your budget issue, I face the same issue, and whilst I would dearly love to upgrade my exhaust system, I simply cannot afford it at present.

Macca.

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Follow Up By: Kazza055 - Thursday, Sep 06, 2018 at 12:36

Thursday, Sep 06, 2018 at 12:36
Macca, as I mentioned in the first reply, the D-Max exhaust is already 2.75" so another quarter inch is not going to provide such a great improvement as it would for a smaller exhaust.

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Follow Up By: RMD - Thursday, Sep 06, 2018 at 12:43

Thursday, Sep 06, 2018 at 12:43
I have a 3"exhaust which is only marginally larger than that of the OE exhaust. A 3 litre diesel doesn't need, can't use, the extra diameter which is larger than a 4.5 litre turbo diesel uses and which has the capacity to expel far more exhaust gas volume than a 3 litre can ever do, at leadt 50% more. Looks good perhaps, doesn't do much though. Maybe an advantage for sudden full throttle acceleration but not for normal use where you are not using full throttle continually.
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Follow Up By: Member - McLaren3030 - Thursday, Sep 06, 2018 at 17:07

Thursday, Sep 06, 2018 at 17:07
Sorry guys, don’t mean to offend, not just my opinion, but according to the diesel experts, a larger exhaust takes back pressure of the engine, helps the turbo spin more freely, lowers fuel consumption, and increases power. Yes, even 1/4 inch, although a 3.5” exhaust will be more beneficial.

Also for those advocating blocking the EGR, a functioning EGR is currently a legal requirement. If you are going to recommend something that is illegal, at least mention this fact, so people know that they do this at the own responsibility.

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Follow Up By: RMD - Thursday, Sep 06, 2018 at 22:20

Thursday, Sep 06, 2018 at 22:20
While a more free flowing catalytic converter may improve flow through rate and also having a dump pipe immediately after the turbo does improve the drop of temp and pressure across the turbo exhaust turbine wheel, having it, you get a quicker turbo spin up and turbo pressure will be able to be developed at lower engine speed but it doesn't make any more kw than before.
It definitely does not provide more economy or power, that is controlled by the airflow in, the turbo pressure set by the ECU and boost sensor, and the amount of fuel injected. So a bigger exhaust, while may have some small advantages, for general towing use you won't know it is there.

Unless you alter it to more injection pressure and more boost and perhaps an alteration of injection timing as well, then the bigger exhaust is still accomodating the same exhaust output as it did with everything OE.

Knowing this, I have only a 3" back to the OE muffler, as it provides the small additions mentioned but the OE size can handle the engine running full throttle without back pressure. Isuzu have done some research on this I believe.
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Follow Up By: Frank P (NSW) - Thursday, Sep 06, 2018 at 23:51

Thursday, Sep 06, 2018 at 23:51
"Macca, as I mentioned in the first reply, the D-Max exhaust is already 2.75" so another quarter inch is not going to provide such a great improvement as it would for a smaller exhaust."

True, but as you alluded to in your earlier reply, perhaps that quarter inch is more significant than it first appears.

The cross sectional area of a pipe is a critical factor that affects gas flow in the pipe.

The cross sectional area of a 2.75 inch exhaust is 5.94 sq inch.
The cross sectional area of a 3 inch exhaust is 7.07 sq inch.
This is a 34% increase, which is not insignificant.
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Follow Up By: Kazza055 - Friday, Sep 07, 2018 at 13:34

Friday, Sep 07, 2018 at 13:34
So Frank, using your rule why not go for a 6" exhaust, it would mean that the engine would actually produce fuel based on your numbers!

The point of my post and as backed up by RMD, the gains to be made are hardly noticeable and people that have done it on their D-Max do not recommend it be done.

I can see the point if you only have a 2" exhaust but the one on the D-Max is more that big enough. As per my early post, I can buy a lot of fuel for what I would pay to upgrade the pipe work.

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Follow Up By: Frank P (NSW) - Friday, Sep 07, 2018 at 23:17

Friday, Sep 07, 2018 at 23:17
Kazza, it's not "my rule", it's fluid dynamics, or part of it at least.

I wasn't suggesting a bigger exhaust would be beneficial to a D Max or any other vehicle.

I just wanted to point out that an increase in pipe diameter from 2.75 inch to 3 inch, while seemingly not much, is a 34% increase in cross sectional area which may have a significant effect on gas flow. There are other factors in the design of the exhaust system that may make that effect favourable, neutral or unfavourable.

How it works for a D Max or any other vehicle I will leave to you, after market exhaust manufacturers and others to discuss.
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Reply By: Jackolux - Thursday, Sep 06, 2018 at 16:14

Thursday, Sep 06, 2018 at 16:14
Just get it serviced checking the EGR , unless you know the complete history of the vehicle it might already have a EGR blocking plate in it ,
Talk to the mechanic about checking / cleaning the inlet manifold , time , cost ect
Might even be worth getting a Fuel Injection place to check the injectors .
Just make sure everything is as it should be before worrying about , chips , tunes , exhausts and don't get sucked into a throttle control.
What size wheels / tyres has it got , std size , diameter is best .
AnswerID: 621061

Reply By: Griff61 - Friday, Sep 07, 2018 at 10:40

Friday, Sep 07, 2018 at 10:40
No one has mentioned getting a Carbon Clean. I had 1 done on my 2007 BT50 130,00kms and what a great thing to get. Power was back like new and also fuel consumption was back. I was having egr valve problems and it fixed that problem also. The Carbon clean was only $180.00 and took 1/2hr to do. If you are in Adelaide Rickos Carbon Clean did mine. Im not affiliated with them.
AnswerID: 621068

Follow Up By: Member - wicket - Wednesday, Sep 12, 2018 at 13:40

Wednesday, Sep 12, 2018 at 13:40
What exactly is involved in a carbon clean, what is the process?
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FollowupID: 893686

Follow Up By: Griff61 - Wednesday, Sep 12, 2018 at 14:03

Wednesday, Sep 12, 2018 at 14:03
They put a air line into the air intake and I think its a Hydrogen gas that runs through the motor. You run it at idle for half hr and then its done. It breaks down the carbon deposits in the engine. Noticed the difference straight away. I got the wife to take it for a drive when I got home and she said it was like driving it from new. I will be getting it done every 20000ks.I was a sceptical about it but it works for sure.
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Follow Up By: Member - wicket - Wednesday, Sep 12, 2018 at 16:43

Wednesday, Sep 12, 2018 at 16:43
Ok, here’s a brief rundown of how it works, surprised that you don’t need an oil anf filter change after though.
https://www.engineclean.uk/how-it-works/
Hey Ron N, what do you think ?
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FollowupID: 893690

Follow Up By: Ron N - Thursday, Sep 13, 2018 at 01:29

Thursday, Sep 13, 2018 at 01:29
Wicket - Sounds like a good move to me. Carbon buildup is the enemy of all motors, and diesels in particular.

In the old days, we used to buy a gallon of "Redex" and trickle it through the intake while the motor was running.
You needed some space to get rid of the smoke and crap that came out of the exhaust when you revved the engine up, after the shot of Redex, though!!

You could also pour a swag of Redex into the sump and run the engine on it at modest RPM - it cleaned out the carbon inside the block, like a dose of carburettor spray cleaner!

And of course, dedicated Redex users always put a shot of Redex in with every fuel tank of fuel, because it was the greatest upper-cylinder lube ever produced!

Then Holts bought out the original Redex company and I don't think it was ever as good as the original Redex.
Remember, this was the stuff that enabled 2WD family sedans such as FJ Holdens, Customlines, and even VW Beetles, to roar right around Australia on "roads" that are classed as "4WD Only" today!!

Cheers, Ron.
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Follow Up By: Shaker - Thursday, Sep 13, 2018 at 08:22

Thursday, Sep 13, 2018 at 08:22
We used to “decoke” petrol engines with a fine spray of water straight into the carburettor while holding the throttle at about 2000rpm.

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Reply By: Ron N - Friday, Sep 07, 2018 at 22:57

Friday, Sep 07, 2018 at 22:57
Scratcher - The Isuzu donk is a good donk, long-lived, and reliable as the day is long.
However, it's no powerhouse, and you do need to expect it to pull back on the hills when pulling around 2 tonnes.

If the power level appears to have dropped off recently, I'd suggest the following;

1. Check valve clearances. Valve clearances should be checked every 50,000kms and if they haven't been done in 114,000kms, you will probably be surprised at the power improvement, when they are brought up to correct clearance.

2. All the hoses in the intake system need to be checked for condition. The separation of the internal layer of the hose is more common than many would believe, and this can happen to all air inlet hoses, brake hoses, and vacuum hoses.
Intake hoses developing splits are a common event, and this can lead to power loss.
This problem is a known problem with late model Isuzu's.
Here is an eBay modification that is worth purchasing (I have no affiliation, or relationship, financial or otherwise, to this seller).

Isuzu D-Max intake piping improvement kit

3. Get your injectors cleaned by an Isuzu truck dealer. Isuzu recommend that their injectors be cleaned every 100,000kms to ensure proper and complete combustion.
This is particularly important with todays injectors, with their finer orifices and reduced operating clearances.

4. Check the air flow rate through your intercooler to the engine, to ensure it meets factory specs. Partially-blocked intercoolers are a common problem. Ensure the intercooler fins aren't plugged, and that outside air flow through the fins is adequate to remove heat.
Cooled air is dense air, and the air reaching the engine for combustion must be cooled adequately.

5. Check your turbo boost pressure. The turbo on the 2014 Isuzu is barely adequate at the best of times, and the engine was upgraded with a VGS turbo in 2017, when it was re-engineered to meet Euro 5 emission levels.
Many things can make turbo boost fall away, and your turbo may be operating below specifications.

The re-engineered Isuzu D-Max engine produces 430Nm of torque as compared to the 380Nm of the 2014 model. This newer model engine is a vast improvement over the previous engine.

Feb 2017 - Isuzu upgrades the D-Max engine to Euro 5

Cheers, Ron.
AnswerID: 621075

Reply By: Member - Scratcher - Sunday, Sep 09, 2018 at 09:42

Sunday, Sep 09, 2018 at 09:42
Thanks Ron,
Will be following up on some of your suggestions next week.

Scratcher.
AnswerID: 621106

Follow Up By: ian.g - Sunday, Sep 09, 2018 at 10:36

Sunday, Sep 09, 2018 at 10:36
Hi Scratcher
Just before you do anything expensive, just try changing your fuel filter, they are very sensitive to any sort of blockage which gives the appearance that you are down on power. May not be this but is a possibility. I don't own a Isuzu but have a RC Colorado which runs the same motor and have seen this symptom on a few before. NB Just because your dealer says he's changed your fuel filter doesn't mean he has

Cheers Ian
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Reply By: Member - Supersi - Sunday, Sep 09, 2018 at 12:57

Sunday, Sep 09, 2018 at 12:57
I agree with Ian.g’s comment. Change the fuel filter, and perhaps it will take a couple of changes 5k apart. I had the same lack of power issue and this sorted it.
AnswerID: 621110

Reply By: Sigmund - Wednesday, Sep 12, 2018 at 13:15

Wednesday, Sep 12, 2018 at 13:15
I tow 1.4 t CT with a 113K km '14 MU-X. Haven't seen a power drop.

What does happen is that at c. 100 kmh the gearing means it's at the start of peak power in 5th (c1800 rpm). You go up a way and then it drops to 4th and you've lost momentum that's hard to regain.

If I'm hustling I'll hit the start of the rise at 105 kmh and manually select 4th at 100 kmh.
AnswerID: 621161

Reply By: Sigmund - Wednesday, Sep 12, 2018 at 13:18

Wednesday, Sep 12, 2018 at 13:18
To add: my mechanic sees turbos and manifolds clogging up from crankcase fumes at around the 160 K km mark. You may not have a problem now but should get a diesel mechanic to clean them up and install a catch can regardless.
AnswerID: 621162

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