Overheating car that mechanics can't fix

Kingkennas.

Where are you located?. Eric.

hi kingkennas had same prob with my patrol td gq. Mechanics tried everything. In the end he replaced engine with reco. Never found the prob, but suggested it could be cracked block.

KingKenas
Have you checked on how many cores are in the radiator, from memory some only had 3 rows of tubes others had 4 rows.
Something to check
Chris

Had the same problem with my 80 series .... try to change the radiator cup. Found my strong enough to hold the pressure on "normal" conditions but in summer when very hot it was not holding and overheating .... Simple and inexpensive exercise .....
Hope it work for you ....

Luca

Kingkennas, have you had your diesel checked for overfueling? More fuel equals more heat in a diesel.
Fitting an egt (exhaust gas temperature) gauge will show if overfueling is an issue.
Regards Andrew.

Had a problem with a 80 series in Darwin ,a 4 core radiator fixed it.,common problem with turbos motor up north.

Have the shrouds been checked for correct fitting, and some 8mm self adhesive foam, door sealer stuff, fitted so that it pulls all the air thru the rad core??

As others have mentioned, is it overfuelling??, its looking like a cracked block, if everything else has been replaced, and its all doing what it needs too.

I would assume you changed the rad cap early on, but its a very good point that was brought up about checking it.

I had one vehicle that had a perished O ring on one of the metal pipes that fit into the water pump under the inlet manifold.
It was fine under pressure, but leaked under vacum.

fine for a few days/ cycles of hot cold, till all the water was pushed out the rad into the overflow bottle, and it overheated.

Trains

Is it losing water/coolant?

If so, could be a dodgy seal on the expansion bottle piping.

Roachie

Fan hubs in Nissan are known to be "dodgey" from new - probably worth going to a fixed fan and do away with the clutch hub altogether.

Also if the vehicle doesn't already have one - consider adding an aftermarket OIL cooler out front.

A lot of engine temp can be shed via the oil system - not just the water pump - radiator method, In fact if there's insufficient oil volume in the sump - it can act like a heat sink and keep storing the heat the radiator cannot shed, because unlike water, the oil will keep getting hotter way past water boiling temp (220 f under pressure of 12 pounds/inch squared or - a little more if you have a 15 psi radiator cap) in effect defeating the water cooling system once it starts escalating up past that 220f mark.

The extra oil volume of the connecting pipes and after market oil cooler helps to increase sump capacity a couple or 3 liters as well as allowing the oil to do some of the cooling that the water cannot do for whatever reason.

Next consider adding a special water wetting agent for radiator coolant - in effect a surfactant!

What can happen is certain frequencies of vibration within the engine when it fires depending on the ignition timing and combined with the speed of the water circulation combined with restrictions within the water jacket - can set up a "harmonics/low pressure" pockets within the blocks water cooling channels - that forms small air bubbles on the cooling fluid side surface of the cylinder bores, and keeps the coolant from contacting the iron and drawing away the heat as it should!

The surfactant / wetting agent helps to prevent the fluid from forming those bubbles be reducing the surface tension of the fluid.

Next - consider adding a poly water tank somewhere inside the vehicle and connecting it to a 12 volt marine deckwash pump - and plumb a half inch reinforced compressed air line (hookah hose works well) to the front of the vehicle and up in behind the grill.

Block the end of the hose in front of the oil air con and water radiators (and steering pump fluid radiator, and transmission oil cooler radiator if you have them) with a plug & stainless hose clamp and fit a couple common fine garden mister sprays before the plug spac3d equidistant about 1/3 in from the side of the radiator and closer to the top of the radiatir than bottom!

Switch the 12V marine pump via the dash

Install a tap (inside the cab next to the on off switch) so you can shut the sprayers off manually when not needed and stop the tank siphoning empty when not in use!

This way - when you notice the EGT's (exhaust gas temps) and normal engine temps gaugue temps increasing (add a Exhaust Gas temperature probe or pyrometer as it is called in the exhaust pipe below where it exits the manifold and joins the exhaust pipe if you don't already have one) - you can turn on the tap and switch the misters out front on via the pump switch from inside the cab while driving.

The water spraying thru the radiatiors cores will act like an old "coolgardie safe" as it evaporates and draw a LOT more temp OUT of the radiators for the oil and water radiators (and air con and trans fluid etc) and everything will cool way down when under load while your driving.

You will see the engine temp gauge drop also the EGT's and if you have them Trans oil temps, and engine oil temps...they will ALL drop as you apply the water!

Also your air con will blow NOTICEABLY COLDER air for a while!

I only use the water boost pump switch etc when towing heavey loads at speed up hills in the heat 40+C days or into strong headwinds etc.

It works - simple as that and when not in use, the spare water is handy for other purposes. In an extreme stranding situation it might save your life. I have an additional snaplock connection plumbed to the rear bumper and a coil of garden hose with fire nozzel in behind the back seat as an emergency fire fighter should I ever get a tyre fire - I can use the water to hose down a molten rubber tyre fire to a temp below reignition point (after I've knocked it down with the fire extinguisher until I get the water hose plugged in and switched on). I carry a total of 4 fire extinguishers between the two vehicles and boat.

It may not save your vehicle trailer or boat etc but possibly a fellow travellers if you happen on the scene in time.

Lots of ways to skin your hot Nissan cat - I wouldn't be expecting Nissan to come up with any answers soon tho.

Might as well do it yourself!

Works for me!

Cheers!

I guess a few obvious causes like dragging brakes, slipping auto trans/torque converter etc should be eliminated first tho!

Cheers

I had a 75 with the same problem. tried everything bar replace the motor. I suspected a cracked head but it would only over heat under "forced" conditions, eg load, hills , air flow as per the test.I decided to get it hot in the workshop. I slid cardboard in front of the radiator and let it idle with the radiator cap off. Sure enough after a while she got hot and bubbles appeared from the radiator. It was then decided the head would come off, The head was "fractured" which means under general conditions it was fine but as soon as it had to work, it would open up and form the "crack". New head and no worries. I cant say I have ever heard of this other than my own vehicle.

Very common with the TD42 motor. I have had three and all of them have done this to a certain degree. The n/a 4.2 in my old GQ was the least to suffer from this but my later turbo GU's are quite bad. If it is happening unloaded and regularly then I would suggest there is a "real" problem but if it is only happening under load then I wouldn't waste any more money on it and ease up on the loud pedal in the most extreme situations. Couple of extra minutes to your trip each time but thousands of dollars better off in the long run. Sounds far fetched but the motor is good to the end of the solid line on your factory Nissan temp guage if all is reading correctly. I have run 110c - 120c all day at times (3/4 and above on Nissan gauge) and to date have seen no detrimental side effects.

My GU (hers now) has done this since brand new and has driven me to the funny farm trying to fix it. Now I just keep an eye on temps via a thousand gauges and just keep driving it. I have run serious temps in this thing for long periods and still it hasn't blown and now with nearly 370 000 km I figure if it was going to go, it would have done so by now.

As others have suggested, forget Nissan most of them are useless without any real answers. Western Plains Nissan up in Dubbo were about the only dealership to be "honest" with me and give me good alternatives but told me not to expect too much though. So if you really want to talk to anyone, I would ring these guys but tell them you are well aware of the "common" TD42 overheating issues and not to bull$h!t to you.

Best regards,
Trevor.

In case you're all wondering, I'm pretty easy on the right foot going up hills, I never let the tacho get over 2500 rpm to look after the engine and annoy the oil companies a little. I've had the head checked when they did the head gasket and it was fine. If it matters the person I bought it off a year and a half ago lived in warm Queensland and the first six months I had it everything was fine, he was the first Australian owner after it got imported and Japan has it's hot days to.

Mechanics say that it's not overfuelling because it's not blowing out black smoke, you hardly see any smoke, it can't be a cracked block because it's not losing one drop of water, I spoke to Natrad in Ringwood Vic who replaced the radiator nine months ago and cleaned it a couple of weeks ago when it turned out to be perfectly clean anyway and he said that it either has two rows like all the genuine ones or three like a heavy duty genuine one and can't remember which one it is, but I'll find out, for memory he put a heavy duty one in, I vaguely remember him saying when he did it. The mechanic checked the water pump by pulling it out and by water flow and said that it's fine, all the belts are new and were checked again when they were pretty new. The air conditioning condenser is clean as anything, it overheats with my driving lights on or off and the engine doesn't have any mods like turbo, supercharger etc. The viscous coupling on the fan is only one week old and the one before that was nine months old and was still 90%, genuine ones.

I'm 90% sure it's three by looking at it the best I can, but I'll check 100% when I go back or see if someone else can tell, the invoice doesn't say. If you've got any tips on easy ways of telling how many fire away. The shroud is tight as and seals beautifully and I can't think of how many times they would've removed it and put it back on.

HI ,
I have had the same problem with my 2.8lt td gq.
With mine the answer to fixing it seemed to be to run a genuine Nissan viscous hub which you have already done and the other thing that i was told was stick to the original radiators. Changing to a heavy duty 3 bar ( one is aluminium other is a diff kind of metal) and the three bar heavy duty holds heat more and lets the water flow quicker through the radiator not letting it cool down quick enough.
The other thing is to let it climb the hills at its own pace. Dont push that foot down = overfueling.
I spent more than $1500.00 on mine before we seemed to have it under control.
Don't know if i was fed a lot of crap but it does seem to have sorted things out.

your driving lights not restrickting air flow try driving with them removed

Hi Kinghennas,

I have a 4.2 Turbo Diesel and it used to over heat until I fitted a 3 inch dump pipe right behind the turbo. I know yours is non turbo so maybe a set of extractors might help.

Goona

Have you had the block flushed. There is a drain plug left side of block at the back. Remove the plug and give it a good flush out. Could be mud in this part of the water ways restricting flow . Removing the plug is the only way to clear it.

Hi, when you say it overheaats is the needle still in the high end of the working area or does it go into the red. If its not in the red its not overheating but running hot but still in the working range. Have a 92 GQ 4.2 diesal which has done 370,000ks with the same symtoms as yours, have been in the pilarras 45degrees out side towing a heavy camper doing 100ks with a/c on and the needle sits just below the line before the red. I have a pyro guage fitted which helps to not over fuel with the foot. The only thing i have done is fit 2 big electric fans on the front running off a manual switch in the cab, turning it on when coming to hills. Have never done any damage to the motor and have a super charger sitting on top for the last 200,000 ks. When going up hills try changing down manually and keep the revs up at about 2800 in each gear and dont labour the motor in low revs. Col

Kingkennas, if you still hit a brick wall after trying all, give Patrol A part a ring in Lilydale, ask for Paul. He lives and breathes patrols.

kingkennas

If you rev the engine a little more going up hills, it can sometimes help, by allowing the coolant to flow faster, but in one of your posts, I think you said that, but did you consider what revs you change down at.

How is the cowling around the radiator ?

I remember a bloke up Wodonga way that had had huge trouble with his cooling on 40 c days, and in the end, he brought one of those hi flow fans, and threw out the viscous clutch.

From memory, the same bloke actually jacked up the bonnet hinges, at the firewall, and let some of the hot air escape via the windscreen.

Looked a little daggy, but it seemed to work for him.

Roachie had issues with summer heat, as well, but maybe it was the bigger turbo he put in his GU, or he just had a hot running motor .

Cheers
Bucky