12HT Engine Oil Pump related extended damages diagnosis and solution

Submitted: Thursday, Jul 04, 2013 at 15:37
ThreadID: 103090 Views:8326 Replies:2 FollowUps:14
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I recently bought overhauled engine and replaced my 2H with 12HT, however they didn't change the oil pump during overhauling of 12HT engine. Few days back when I drove my HJ60 landcruiser on high RPM I noticed noise in engine and felt like it had a knocking sound and also felt it was missing as well, however when I reduced the RPM on drive it seemed OK.

My mechanic says that my oil pump doesn’t work well during higher temperature and as a result it has also damaged the main begin or has damaged part of main begin (I may have spelled wrongly) and suggests to repair oil pump as it will become like new and says I would need to even change main begin, new piston rings, get overhaul kit, seals and go to lathe machine.

Would someone please advise if the above diagnosis and solution seems reasonable and if there is anything that he may have missed out to check further. Or if above extras can be avoided and just limit to change of oil pump and main begin? Also need advise if oil pump can get reconditioned like new?

Many thanks in advance
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Reply By: Ross M - Thursday, Jul 04, 2013 at 17:31

Thursday, Jul 04, 2013 at 17:31
The oil pump in a 12HT is mounted in the front timing cover housing and is driven at crankshaft speed by the by the crankkshaft. The inner pump element rotor is a ring which fits over the crankshaft and is driven by a drive spline on the crankshaft.
Apart from a total failure I cannot see why it would ever not pump oil if it's working clearances have been checked by the engine reconditioner. It is possible they never looked at the pump though.

If the pump wasn't working from the beginning then the engine wouldn't last 5 minutes from the first startup.

Do you know if you have oil pressure?
A 12HT and also a 2H will shut the engine down if no oil pressure is there for longer than about 20 seconds.

If you wish I can email the oil pump specs to you.

If the engine was reconditioned, it would be my guess the person doing the job may not have replaced the piston cooling jets in the block or they are faulty and you are losing lots of oil pressure through them.

Many Orstarayans mechanics, say. "berrins" when they really mean to say, if they spoke properly, is "bearings". The engine has 6 big end bearings and 7 main bearings all fed oil from the pump.

If oil pressure is low or not there they will become damaged and need replacing, but the source of the problem has to be found before they are changed.
If any BERRIN failure has occurred then the crankshaft may may also be damaged.

The oil pick up from the sump, if fitted incorrectly can cause air instead of oil to be drawn into the pump and this will cause failure as well.

I would ask a 4wd service centre who have had experience with those engines and will possibly give you a more accurate diagnosis than an average mechanic.

A properly maintained 12HT "usually" will do over 500,000km before the oil pump would any cause trouble.

Ross M
AnswerID: 514274

Follow Up By: Naveed Merchant - Thursday, Jul 04, 2013 at 19:55

Thursday, Jul 04, 2013 at 19:55
Thank you Ross

My mechanic also reached to same conclusion as diagnosed and advised by you and he says even crankshaft is damaged. So for me its like starting from all over again.

Is there anything else that i should advice my mechanic for overall engine rechecking just to make sure everything is OK as a general checklist for the engine. I just want to avoid any other potential issues at later stage.

Many thanks

FollowupID: 793236

Follow Up By: Tim HJ61 (WA) - Friday, Jul 05, 2013 at 01:25

Friday, Jul 05, 2013 at 01:25

I recommend you get a second opinion.

What your mechanic is proposing is a very expensive rebuild of the engine, essentially overhauling what has already been overhauled.

I have no disagreement with Ross M's assessment, but all of us are going by what you have posted, which is what you have been told by your mechanic.

A second opinion, or third opinion, and some hard number crunching to see if you can pick up a second hand motor for cheaper than a rebuild, might be an option.

Where are you Naveed? We might be able to suggest a suitable place for an assessment.

When you say you drove it at high RPM, what RPM are you talking about? 3000, 3500, 4000? More.... eeeek.

What does your oil pressure gauge say? They are not always reliable, so part of any assessment should include temporary removal of the oil pressure sender and installing a known reliable gauge that can accurately tell you what pressure is being produced.

What was the higher temperature you experienced - 45°C - 50°C

Are you running standard diesel fuel? Has there ever been any petrol added into the tank that you know of? Such mixtures can be used in cold climates, then in the heat the petrol can form vapour lock and cause preignition. I have experienced this and it felt like the bottom end of the motor was dropping out. Once flushed and running on straight diesel, then engine ran perfectly and has continued to do so.

Oil pumps are highly reliable, as they are sitting in oil all the time. They last for a very very long time. There is a pressure relief valve that sometimes sticks and causes too high pressure, but I've not heard of the oil pump itself causing a problem.

I agree with Ross that installation problems can cause serious issues such as he has described.

All this is speculation Naveed. Another opinion is highly recommended, and some definitive testing of your oil pressure. A rebuild will cost thousands.

FollowupID: 793271

Follow Up By: mountainman - Friday, Jul 05, 2013 at 04:27

Friday, Jul 05, 2013 at 04:27
the guy is from Pakistan buddy..
sounds like another rebuild..

ad throw the old 2h back in and when funds allow, send it to another mechanic.
and rebuild it..
mind you a bloke I know said his engine was stuffed...
ended up being a water pump..

definitely worth getting another shop to look over it for sure..

yes 12ht can last 500k, but its the nut behind the wheel and the maintenance as well that helps..
and also a bit of luck, hoping nothing lets go in a big way in that time..
FollowupID: 793272

Follow Up By: Naveed Merchant - Friday, Jul 05, 2013 at 11:02

Friday, Jul 05, 2013 at 11:02
I was wondering if there is anything i can do like perhaps send pics of any engine sections on this forum and perhaps ask him any brief set of checklist of questions with sending pics on this forum to validate it as i want to avoid repetition of works already done and limit him to carrying out repairs of what is really required.
FollowupID: 793284

Follow Up By: Tim HJ61 (WA) - Friday, Jul 05, 2013 at 22:00

Friday, Jul 05, 2013 at 22:00

The correct diagnosis is the critical thing. I am not confident you have the correct diagnosis yet.

To prove his theory on the oil pump, he must first establish what the oil pressure is inside the engine. To do this, he must install an accurate oil pressure gauge into the side of the engine behind the injection pump. He must first remove the existing oil pressure sender, it is approximately 40mm across and has one electrical connector on it. Once he has installed his own accurate oil pressure gauge, you will both be able to gain a more accurate impression of what is happening inside the engine. The specifications for correct oil pressure are in the repair manual.
Page LU3
Oil pressure:
At idle 0.3 kg/cm2 (4.3 psi. 29 kPa)
or more
At 3,000 rpm 2.5 - 6.0 kg/cmz
(36 - 85 psi. 245 - 588 kPal

A manual is available for you to download at my website

There is a section in the manual on how to check for oil pressure problems. Correct diagnosis is the first issue.

Please let me know if you do not understand these instructions. I gave you similar hints in another reply, but you've come back asking for the same thing. I'm assuming for now that you've not seen what I wrote before. I asked the questions to help us give you a better diagnosis.



FollowupID: 793339

Follow Up By: Naveed Merchant - Sunday, Jul 07, 2013 at 14:01

Sunday, Jul 07, 2013 at 14:01
I will call my mechanic today and give him the above advise to check oil pressure as suggest above .. however he had told me the oil pump was wrongly installed which caused the failure problem and as a result damaged all bearings and crankshaft and says i need to recondition oil pump so that its like new

He has already removed engine from my HJ60 so need to check if he can test oil pressure.

FollowupID: 793445

Follow Up By: Tim HJ61 (WA) - Sunday, Jul 07, 2013 at 14:35

Sunday, Jul 07, 2013 at 14:35

He will not be able to check oil pressure unless the engine is running. He is unlikely to want to hook up a radiator and fuel supply with the engine out of the vehicle in order for it to be run and bench tested. But it would be 'possible'.

So for now it seems you have to trust his diagnosis. You must ask him to keep all the old parts and even get him to show you what went wrong and what it is that he is doing that is going to fix it.

When you were driving the vehicle, did you ever notice if the oil pressure gauge was showing any reading??

If this mechanic installed the 12ht into the vehicle, did he not check the oil pressure was satisfactory before handing it over to you?

FollowupID: 793446

Follow Up By: Naveed Merchant - Sunday, Jul 07, 2013 at 17:51

Sunday, Jul 07, 2013 at 17:51
Just spoke to mechanic and he says he took the oil pump to a specialist and he 100% confirmed the pump was faulty but says the ring also needs changing as the once the overhaul kit is changed (i think its the seal thingy which breaks off) then the rings wont fit as these rings creates its own space. besides he has also confirmed crank shaft and bearings needs changing.

I wish he had checked oil pump pressure on engine so i guess I will go by his diagnosis.

Does it make sense to change rings a these were new rings when it was overhauled.

FollowupID: 793462

Follow Up By: Tim HJ61 (WA) - Sunday, Jul 07, 2013 at 18:40

Sunday, Jul 07, 2013 at 18:40
Quoting from your followup
"besides he has also confirmed crank shaft and bearings needs changing."

There is one word in that sentence that I hope is not the case for you. This is the word ''and". Yes it will most likely be necessary to replace the crankshaft bearings, but to replace the crankshaft AND bearings is a very expensive operation I imagine. I have some recollection the crankshaft from a 2h and a 12ht are the same which may save you some money - if that needs to happen. Generally it would just be the bearings, and the crankshaft cleaned up at the machine shop with a proper lathe.

Regarding the rings. I assume he is talking about the piston rings. In a full overhaul, yes the pistons and rings are replaced. They are unlikely to be a very expensive addition to the cost, so you might as well agree to having them replaced. There are also bearings inside the pistons where the conrod connects to the pistons.

The pistons are the things that go up and down really fast. The crankshaft is the thing - a long shaft - with lots of bumps in it that act as a crank - an offset lever that the piston pushes on to turn the up and down motion of the piston into a round and round motion that drives the car. In between the piston and the crankshaft is a rod, called a conrod, or connection rod.

There are bearings at the top and bottom of the conrod. One set, the big ones on the bottom that go onto the crankshaft, is called the big end bearings. The other end that go onto the pistons are much smaller, so they are called the little end bearings. There is a heavy rod, called a gudgeon pin that goes across the inside of the piston and the conrod is held in place by this gudgeon pin. The little end bearings are flat bearings, i.e. not roller bearings, that allow the conrod to move on the gudgeon pin.

The big end bearings on the crankshaft are also flat, i.e. not roller bearings, as are the bearings on the crankshaft.

Given your specialists believe you have suffered from low oil pressure, ANY and probably ALL of these wearing surfaces will be best replaced whilst doing this job.

This list would include all engine bearings and piston rings. Not the pistons themselves unless they are damaged.

I trust this helps you understand a bit more of what the mechanics are saying to you and why.

It will also be very important for them to make sure the oil squirters that pump oil onto the underside of the pistons (to keep them cool under the high temperatures created by the direct injection motor), and the oil pickup from the sump, are screwed in correctly with proper sealant to ensure no loss of oil pressure. Bob referred to these issues back at the start.

FollowupID: 793464

Follow Up By: Naveed Merchant - Tuesday, Jul 09, 2013 at 00:23

Tuesday, Jul 09, 2013 at 00:23
My mechanic says as follows:

Crankshaft: he says took crankshaft to the lathe guy but he says its not usable as its damaged and says he will get a second hand crankshaft. I was wondering if i can provide pics of replacement used crankshaft to you once he gets it from the car junkyard as just wanted to avoid any goof ups... the new ones aren't available and i guess they might be expensive. Also wanted to show you pics of existing crank shaft after its was cleaned.

Rings & main bearings: Yes rings and main bearings (locally its known as main begin) needs to be changed. His diagnosis is still faulty oil pump due to its wrong placement and worn out bush of oil pump but could it be caused by the dust intake? as i think my air filter (based on oil) and that needed change and even the air intake was open for 1 to 2 weeks as it was running on without turbo due non availability of used turbo

Wearing surfaces: Would you please let me know which wearing surfaces would need replacements if i can post any pics of any specific sections to you.

Oil Squirters and oil pickup: Ok this is also a checklist to make sure these are fixed and sealed properly. I assume by oil pickup you meant oil pump?

FollowupID: 793573

Follow Up By: Tim HJ61 (WA) - Tuesday, Jul 09, 2013 at 10:10

Tuesday, Jul 09, 2013 at 10:10
You drove the vehicle without an air filter for two weeks???

The wearing surfaces are the ones that have bearings in them. Your mechanic seems to have the right idea.

The oil pickup is the tube that sucks the oil from the sump into the oil pump. As Ross said ages ago, if this is not sealed correctly it will suck air.

I'm guessing you didn't get a GTurbo?

FollowupID: 793586

Follow Up By: Naveed Merchant - Tuesday, Jul 09, 2013 at 12:30

Tuesday, Jul 09, 2013 at 12:30
My mechanic told me that its ok to drive in city until gets the the turbo from junkyard.. which took 2 weeks :( i hope this hasn't damaged other components

I will provide feedback from this post to mechanic.

FollowupID: 793593

Follow Up By: Tim HJ61 (WA) - Tuesday, Jul 09, 2013 at 15:32

Tuesday, Jul 09, 2013 at 15:32
Now you have a new turbo and a new engine, don't drive without an air filter ever again. Okay!

FollowupID: 793606

Follow Up By: Naveed Merchant - Tuesday, Jul 09, 2013 at 19:25

Tuesday, Jul 09, 2013 at 19:25
Ross , Tim ... Thank you so much for all your advice .. you all have made my day.

I wanted a quick advice what type of air filters would you suggest i use as i currently have oil based air filter. I sometimes offroad in very dusty environment with very fine ground sandyish particles and 4x4's ahead mine throw out thick layers of dust sand. I had noticed sand or dust particles prior to the day of breakdown of 2H engine during my last offroad trip
FollowupID: 793618

Reply By: Tim HJ61 (WA) - Sunday, Jul 14, 2013 at 11:49

Sunday, Jul 14, 2013 at 11:49
Any updates Naveed?
AnswerID: 514779

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