oil to thick? gq

Submitted: Tuesday, Mar 28, 2006 at 09:05
ThreadID: 32245 Views:10241 Replies:5 FollowUps:16
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Hey Guys, I have a nissan gq 1989 td42 turboed diesel 235000km and was wondering after towing (90kph) a camper in south aus on a 37 degree day noticed the temp a little too hot for my liking.Prior to the trip I added a tube of silicone oil into the viscous hub,flushed the radiator out,installed a new thermostat 77 degree,got the engine dyno tuned and the injectors done up along with the injector pump set up properly.Took the nissan badge off the front grill,installed a snorkel.

After all this I changed the oil to Penrite hpr 20w60.Question is perhaps this is a little too thick?Any suggestions before I start changing to a bigger core radiator etc $$$.

OH PS:The turbo at its hottest ran up to 563 degrees C

regards andy
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Reply By: Brid from Cost Effective Maintenance - Tuesday, Mar 28, 2006 at 09:35

Tuesday, Mar 28, 2006 at 09:35
Hi Andy

It may well be too thick. The more viscous the oil is (above design viscosity) the more fluid friction due to excessive churning. Also increrased drag and reduced horsepower can result. The single most important quality of oil is its viscosity.

20W60 is a couple of grades higher than the standard 15W40 normally recommended. There's no problem going one grade higher (eg 15W50) for countering a bit of wear, running higher ambient temperatures, or working hard, but there is a balance point.

Hope this helps
AnswerID: 163389

Follow Up By: Peter - Tuesday, Mar 28, 2006 at 09:45

Tuesday, Mar 28, 2006 at 09:45
Have a 2003 GU 4.2TDi and run 20W60. Haven't had any overheating problems (even when pulling 1.5 tonne van). Nissan recommends 20W50.
Brid bearing in mind Nissans recommendation of 20W50 do you consider 20W60 to be a cause for concern? I'm upgrading to a 2.8 tonne van shortly so may have to reconsider my oil options.
I used the same oil (20W60) in my Defender for 5 years towing the same van and never have problems with oil (everything else tended to fall off but the oil was always spot on a the 5000km changes)
FollowupID: 418136

Follow Up By: brd - Tuesday, Mar 28, 2006 at 20:15

Tuesday, Mar 28, 2006 at 20:15
I don't think there is any cause for alarm as far as lubrication protection goes in this particular type of engine. In addition, oil degradation due to shear out of viscosity index improvers will be less of a worry than for a lighter weight oil. Cheap oils often drop out of specification (to a lower viscosity) during the recommended oil service period, so you can lose protection.

My comment above relates to optimizing performance...providing the highest viscosity for protection, without causing excessive fluid shear (which can elevate oil temp) and horsepower losses due to fluid drag.
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Reply By: Voxson (Adelaide) - Tuesday, Mar 28, 2006 at 09:42

Tuesday, Mar 28, 2006 at 09:42
Slow down on hot days..
AnswerID: 163391

Reply By: warthog - Tuesday, Mar 28, 2006 at 10:11

Tuesday, Mar 28, 2006 at 10:11
Rgardless of the viscosity, you are using the wrong oil for that motor. Use an oil that is designed for japanese diesel engines such as castrol jmax or caltex delo cxj. This is a document that has been around a while but explains the engine oil requirements of your engine well. You could also ring the technical advisory service of the various oil companies and see what they recommend. The caltex no is 1800 815 823.

The td42 motor can have cooling concerns in hot weather when working hard, Roachie has more experience than most. Ours will sit on 115 - 120 towing our camper in the conditions you describe before it gets warm enough to switch the aircon off, which is my cue to slow down.
AnswerID: 163396

Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 11:06

Tuesday, Mar 28, 2006 at 11:06

Although I agree with you in that he is using the wrong oil and I also agree with the document from Caltex, the TD42 is not a typical Japanese engine.
IN fact if you look at the table of differences at the end of the document you will find that the TD42 fits the american engine design more than the japanese design, this is because the td42 engine design was initially copied from the Perkins engine for use in small trucks and buses in the 80's (like the civilian) bus still being used today.

Also if you examine the pistons from a td42 engine, they fit more closely with the american design. The sump capacity to power ratio and service intervals also reflect that of american designs due to carbon deposits.

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Follow Up By: warthog - Tuesday, Mar 28, 2006 at 12:22

Tuesday, Mar 28, 2006 at 12:22
I am not a mechanic and have not seen the pistons on a td42 so I'm happy to stand corrected on piston ring location. The caltex tech I rang though was adamant their primary recommendation for my td42t was delo cxj. I understood the reason nissan specs 5k oil changes for this engine was that the typically american biased formulations in the diesel oils on sale in Aus dont handle the soot loads the td42 generates.
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Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 12:34

Tuesday, Mar 28, 2006 at 12:34
I can (once I get hold of it) post a picture of a TD42 piston.

In fact, a few years ago we had a perkins motor and a td42 side by side (pulled apart) and although Nissan had made some significant changes to make it a faster revving, more modern engine, the similarities were amazing!!
Nissan has modernised this engine even more when they added a turbo to it in 1999, ie: lighter pistons, different camshaft and injection pump in an attempt to get it to comply with emissions.
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Follow Up By: Member - Roachie (SA) - Tuesday, Mar 28, 2006 at 12:47

Tuesday, Mar 28, 2006 at 12:47
Seeing as how my name has been mentioned I thought I'd better throw my 2 cents worth in at this point.

I firmly believe there are 2 separate, and largely unrelated issues here.

1. The grade oil being used.......I'm no expert but I would not be using that grade (or brand) of oil. I now use 100% synthetic AMSOIL and have just sent a 4th sample off to the Castrol Lab for analysis, with the oil having done 25,000klm since it was put in the motor. This oil is 15W40 and the next lot I have ready to instal when needed is actually 5w30.

I am not convinced the oil grade/type/brand being used is a cause of the motor getting warm.

2. The TD42 does get warm......get used to it!!!! hahaha I have gauges for all sorts of things in my cockpit. One of them is a VDO water temp gauge; sender is in top radiator hose. On an occasion at New Year when it was very hot, I managed to drive about 250klm or more with the standard gauge just below the 'danger' zone on the right side of the gauge. Meanwhile the VDO gauge was telling me the real temp was about 118oC. Okay, that IS warm....but it's NOT "overheating" as far as I'm concerned. I didn't back off from the speed I was travelling (around 100k/h) and I was well loaded up with a combined gross mass of about 4.5T. The truck did not lose power etc and as soon as I was able to get onto any slight downhill section, the temp dropped. All this time the EGT (above the turbo) was sitting on no more than 550oC, which equated to about 430oC in the dump pipe. Note too that I have disconnected the switch in the bottom radiator tank which triggers the air con to switch off if the water temp gets to a certain level...... as far as i was concerned the air con should not switch off when it's a hot bloody day!!!As far as EGT's are concerned, I have never had it hotter than 585oC/450oC respectively. I attribute these relatively low temps to the 3" exhaust system.

So, my advice about the heating situation is not to get too hung up about seeing the Nissan gauge go above half way; at least until it gets into the twighlight zone on the far right hand side. Nissan even say that the vehicle is designed to operate with the gauge going that high and not to worry about it.....I know it is easier said than done!!!!

Hope this helps.


FollowupID: 418168

Follow Up By: Member - Tony G (ACT) - Tuesday, Mar 28, 2006 at 13:05

Tuesday, Mar 28, 2006 at 13:05
G'day Roachie, been following your so called overheating for some time now, and I read with interest that you disconected the cutout switch for the A/C at the bottom of the radiator.

Did you just pull the wire off? Or some other fix?

Its a pain when the air cuts out and the needle has only moved a poofteenth. In my case to half or straight up and down.
FollowupID: 418170

Follow Up By: Member - Roachie (SA) - Tuesday, Mar 28, 2006 at 14:13

Tuesday, Mar 28, 2006 at 14:13

Too easy really........

On the bottom of the radiator there is a screw in plug on either side, each with 2 wires coming out. The one on the passenger's side is the one that triggers first, cutting off the air-con. If you look closely, the 2 wires go to a 2 part plug/joiner that can be squeezed in the right spot to release the lock and then you can pull it apart. This will make the switch inoperative.

I have left the other switch (on the drivers side) in tact. It is designed to trigger at a slightly higher temp and turns on the air-con's electric fan in front of the condensor behind the grill (but the air-con compressor does not cut in). The idea of this is to get some extra air flowing through the radiator to aid cooling.

I have taken this one step further and fitted a 14" Davies Craig electric fan on the opposite side (driver's side) of the air con condensor, which i can turn on at any time with a switch on the dash.

To protect myself from any claims for damage........I must add a disclaimer that this set-up works for me because I constantly monitor my gauges (especially the VDO water temp gauge) and feel confident that I am always aware of what the water temp is. What I would like to do, is to fit another temp sender unit in the bottom hose so i can see how much difference there is between the hot water going into the radiator, compared to the water that has been freshly 'cooled' by passing through it's cores. I have a large PWR radiator (all aluminium) with 2 x 26mm cores.....compared to the standard plastic-tank unit which has 2 x 12mm cores. But after all that, the water is still so hot that if I leave the previously mentioned switch connected up, the air con still cuts out, so I'm not convinced the big PWR is doing any better job than the standard Nissan radiator.

The real unknown issue with some of the 4.2L motors is the story that says there were a number of them manufactured and the casting sand was not fully flushed from the water ways....also the possibility that some of them have had head gaskets fitted without all of the water way holes having been properly punched out. I have no first hand confirmation as to whether either of these scenarios is true or not.


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Follow Up By: warthog - Tuesday, Mar 28, 2006 at 15:07

Tuesday, Mar 28, 2006 at 15:07
I had a look in the Gregory's manual #519 (the newer one that also covers td42 engines) and it has a picture (pg 117) of a td42 piston. The top compression ring is a fair way down from the top of the piston. It looks remarkably similar to the picture in the caltex document of a Japanese piston and for that matter European which I believed perkins to be. It certainly does not show the piston ring near the top of the piston as is the case with an American engine in the Caltex document. Now I am confused.
FollowupID: 418178

Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 16:15

Tuesday, Mar 28, 2006 at 16:15
There are no diesel engines which have the compression ring near the top of the piston such as the caltex document, I assume they did that for illustration purposes, I would like to challenge Caltex and show them a typical American Allis Chalmers piston or a caterpillar piston and ask them to "explain" their rationale for "american-european-Japanese" document.
However I agree with them on other parts of their document and the need for detergent on certain engine designs but not necesarilly american-european or japanese.
FollowupID: 418183

Follow Up By: Exploder - Tuesday, Mar 28, 2006 at 18:45

Tuesday, Mar 28, 2006 at 18:45
5W30 Gee Proceed with caution, I assume this has been recommended by a Diesel Fitter, running too thin a oil is just as dangerous as running oil that is too thick.

Andrewv> Maybe try HPRDiesal 15>15W50 may be better on the mark, but if Nissan recommend 20W50 I can’t see 20W60 causing that much of a problem.
FollowupID: 418206

Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 20:26

Tuesday, Mar 28, 2006 at 20:26
Nissan recommend 15 w 40
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Follow Up By: 120scruiser - Tuesday, Mar 28, 2006 at 20:44

Tuesday, Mar 28, 2006 at 20:44
Hi Roachie
I was talking with this mob
yesterday and they faxed through a document which made very interesting reading about water pump pressures, head of water required and head of water available. I was trying to get information out of them about these 4.2 Nissan diesels but I am still waiting to hear back. Aparently they fixed a friend of my mates nissan with head work and a modified water pump. I am still trying to verify it because if it is true I would be happy to work with them and send them work as well as purchase this so called modified water pump off them. I was waiting to hear back from them prior to posting but I thought I would mention it in this thread.
I will keep everybody posted as I emailed them tonight so will check the emails tomorrow.
FollowupID: 418232

Follow Up By: Peter - Tuesday, Mar 28, 2006 at 20:52

Tuesday, Mar 28, 2006 at 20:52
Just checking my manual for the Patrol (page8-5) and it states:
For hot and warm areas (I live in Queensland so am considering that to be warm) 20W-40 and 20W-50 are suitable. (These oils are recommended for use in temperatures betweeen minus 10 and plus 40 degrees C).
If Nissan apparently can't get the correct oil right, what hope do us mere mortals have?
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Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 20:57

Tuesday, Mar 28, 2006 at 20:57
A friend of mine did the mod from this people to his GQ, water pump, a head modification to get rid of aireation etc etc....

Didn't make much difference.... Well, yes it did to his wallet!!
FollowupID: 418238

Follow Up By: GUPatrol - Tuesday, Mar 28, 2006 at 21:07

Tuesday, Mar 28, 2006 at 21:07
The manual also states that 15w-40 is suitable from -20 to ...... and an arrow that goes to who knows what hot temperatures....

The thing is that the oil plays a crucial role in getting rid of heat from under the pistons, the correct choice makes a big difference.

There was one positive outcome from a fellow in the Patrol4wd forum who had overheating problems using Penrite 20w-50 and his overheating problems dissapeared when he went to Castrol RX super 15W40
FollowupID: 418240

Reply By: Truckster (Vic) - Tuesday, Mar 28, 2006 at 13:35

Tuesday, Mar 28, 2006 at 13:35
Go with Shell Rimula X with genuine filters every 5000klms.

Nick W off GQ list got 570,000klms out of his before he removed the head - he could still see the cross hatch marks in the bores from NEW...

PS. Turbo GQ's always run hot. Go with an aftermarket Temp gauge to be precise.
AnswerID: 163439

Reply By: Bilbo - Tuesday, Mar 28, 2006 at 23:08

Tuesday, Mar 28, 2006 at 23:08
The TD42 in my old 1989 Ford Maverick ran hot when it was hot outside for 11 years. It was always in the top half of the gauge. I took no prisoners with that thing. It never did it any harm, never blew a head gasket, still pulled like Kings Cross Hooker, started first time very time, always a good clean start even on freezing bush mornings, never made smoke - except at 120 kmh with 6.5 tonnes all up !!

I changed the oil and filters every 5,000 kms, usually used Valvoline (ordinary vanilla stuff).

Never missed a beat - ever.

I've yet to hear of or see a TD42 that has blown up big time.

Cane 'em, they love it.

AnswerID: 163558

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