Overheating GU...again: follow-up to Post 22,807

Hi Roachie,
I have been keeping tabs on this thread because I have the same sort of thing happening with my 4.2 non-turbo. I am leaning towards the bottom hose sucking in during hi revs. I plan to replace both hoses b4 my trip to Innamincka so i will know sometime in July if that solves the problem.

Its a bit cold around ol' Sydney town at the moment so the temp is running a bit lower in the gauge. But when i am away pulling a campertrailer and fully loaded, i am sure i wil get a good indication of how things are going.

Ga'day Roachie . Just reread that post 22,807 as i also have the same prob . So , come on Waterpumpman , we're all waiting . Errol

I have just added this reply to that post and this is what I know about the subject which is what I learned from a friend with the problem.

Below is what I posted on your previous thread:

I read with interest!! but... what about those sports cars which have the radiator much lower than the engine block? They still work and very efficiently... although they do have a de-ariator sitting somewhere up in the suspension tower on close to the firewall. THe new 4.2 patrols have such deariator and a new radiator design and yet they still overheat...

Now I am going to tell you the story of my friend with a 4.2 TD GQ.
He tried (we as I helped him) and others as he worked in the automotive industry, everything, when I say everything it means the lot...
Radiator, electric fan, new viscous, thermostats, with without, head (new head), hoses, not sucking, bleeding etc etc...
Then he went a little further and increased the size of the water galleries inside the engine, then he got to talk to someone in Melbourne (I think) who mentioned the water pump and also a dearieator kit which is supposed to get rid of steam in certain parts of the engine.
There was a test method included in the kit which we did one afternoon, I can't remember exactly but the amount of bubbles and soda looking water was amazing.... We then replaced the water pump with this new one and its new impeller, and also the kit which took a whole afternoon to fit, the "after" test was much better not as many bubbles, but still overheating although slightly better....
He then decided to make a radical change and modify the way the water circulates (in other words he modified it to work like the new 3.0L engines and many falcons etc) which is more efficient??
That had an effect but not yet OK, his GQ was still getting hot but not as much.
I will add that everything was in perfect order, the engine performance was OK, timing was checked, the pump had been fully rebuilt and the injectors had been done etc...
The conclusion while towing a car trailer with a broken down Rangie on it from Fraser Island back to home was that if he backed off it would not overheat which makes it in his words not good enough (and I agree in a way) because up hills you can't backoff but I would be very interested to know what is that makes these engines rise temperature.
One more thing, at some point he even removed the grill, bullbar and everything to allow more airflow and the test proved to be fruitless....
In my opinion having seen many different engine designs and many engines pulled apart, this engine does not have the capacity to get rid of heat by design, the cast iron head and block don't have big enough galleries to get rid of the heat generated by the applications we use it on today, it was designed to be pulling a bus a slow speeds in a naturally aspirated form.
But I welcome other's opinions... as I am not an expert and my theory cannot be tested unless we can talk to the engineer who designed it.
Will

Gday all

(The pumps I have tested so far make really great milkshakes), For this to happen the cooling system would have to have air pocket’s in the engine or radiator, and for this to happen the system would have to be reasonably empty. IMO by no means a fact.

I new a mechanic who fitted a electric water pump to his high Pro-Formance V8 as he wanted better cooling (Did not talk to him about the details to much as this was about 4 years ago) But he did say that it ran a lot cooler.

Just my opinion as I am no cooling system expert, But I would say that most of the problems you are having are associated with airflow, weight and the larger capacity radiator and that poor standard pump struggling to move all that water around. The electric pump would be a good option as it would probably be a lot cheaper than getting a hand made Pump and impellers.

Maybe you could work out a advertising deal with the electric pump company if it works.
Something like “Electric pump solves 5 year overheating woes on Patrol”.

How many Litres is your radiator/ cooling system anyway?

Good Theory GU Patrol a real possibility!

Good luck with it all anyway.

Hello Roachie,
I've been following your conversation with "waterpumpman" in the other thread with a great deal of interest, for no other reason than I hate to see people have troubles with something they paid a great deal of hard earned for.
One thing that sticks out for me, "waterpumpman" has probably forgotten more about engine cooling than I'll ever know, but he's dangling carrots.
Come on "waterpumpman" drop the carrot, spill the beans, kill the cliche's and come up with something concrete.
We are really intereseted in what you have to say,

Geoff.

G'day Roachie, just a word of warning to all about Electric Water Pumps and turbo diesels, I tried one on 2.8 TD Nissan and no matter what I did, even running it flat out, it could not cool it. Eventually, though I can't prove it was due to the electric water pump, the head gasket went. Was no problem before I started mucking around, very expensive lesson. Just my two cents worth.

Roachie, the electric pump replaced the mechanical pump, was run with the water pump controller. I bought a new water pump, machined the impellors off and ran that, to allow the belts to run as original. Didn't work.bleephappens.

Roachie,
Know nothing about Patrols but I had an overheating problem with my NP 2004 DiD Pajero. So have a number of other NP Diesels as well as some NM Petrols (3.5L petrol 2000 to 2003).

Around town and towing at low speeds - no problem at all.

Towing an 1800 kg caravan out of Lithgow towards Bathurst was the first time it overheated. First Mitso dealer, (Bathurst) said can't find anything - it must be your non-genuine bullbar.
Second Mitso dealer (Dubbo) agreed there was a problem and had the top and bottom radiator tanks removed and the radiator was found to be partially blocked (car had only doen 17000 kms at this stage). Drove on but still had the problem if I droive in Auto. OK if I locked the car in 4th and drove at aqbout 90koph.
Third Mitso dealer (Townsville) found blown head gasket. and the radiator still partially restricted. Head gasket replaced, system flushed completely and it has been OK since. Now 46,000 kms.
Theory is that there was a "chemical" reaction" which caused the coolant to gel but Mitso have never acknowledged this. They just say use only genuine Mitso coolant and NEVER mix coolants.

PS the coolant in my car had not been changed since new when the problem first appeared.

Roachie,
Just reading above were you suggested your VDO gauge is probably accurate, but weren't 100% sure.
Quick calibration check is make an ice slurry in a container and immerse sender. Should be real close to 0 deg C.
Boil the billy and drop the sender in it. Should read real close to 100 deg C.

The rough but accurate boil the billy calibration is the one you want as that's the end of the scale you are working at.

Geoff.

Hi Roachie,
You mentioned earlier that you are running 11.75 psi boost. I have a 100 series with an aftermarket Denco and all I run is 5 psi which I am told is pretty much standard. I get as much grunt as I need to tow the van and it's definitely much better than the standard 1HZ motor. The point I'm making here is that the more boost, the more power and of course, the more heat is generated. It would be interesting to hear what level of boost others are running and whether the overheating problem exists at lower boost levels.
Cheers
Gerry

G'day Russell have you thought about that the poor old girl is draging around a lot of extra weight see ya sad-dy all being well.

Roachie,
One thing to support my theory which I forgot to mention is the fact that the TD27 engine used in Terrano I and II has the same temperature issues, yet it is a smaller engine but with the same head design, it is in fact a cut down version of the TD42.
They were having temperature issues in Europe and in Australia when tested in sand....
Read post 23899
Will

Roachie,
Am not sure if you remember me but I had the turbo modified at MTQ toowoomba abiout 2 months ago ?? not sure on exact date but I have done 16 or 17 thousand km's in this time and travelled between wangaratta in Vic to as far north as Townsville and west to Emerald Roma and Goondiwindi (all in QLD). With the various ambient temps ranging up to 30c, my driving style has not been set by the vehicle's running temp (as it used to be). I tow very heavy loads and load the inside of the vehicle to it's max and beyond, even fully loaded and for testing only I have driven my vehicle harder than I normally would with no overheating to speak of yet!!. Have been a few times 130-140 for 40/45 mins in 4th gear with max temp 110c. Am still trying to organize a couple of days to come and see all you good people at Birdsville in July, but as you maybe able to tell driving is the last thing on my mind on my days off (too much driving on my days on). My final verdict on my vehicle will now have too wait for summer, but all indications are good.
In regards to OK running temps, many radiator people up here have suggested to me 110 for short periods is fine, mine used to run at 100-110c nearly all the time except when it was hotter than this ( as much as 118c ). I currently have 219000km on the clock so reliability at high temps doesn't seem to be a prob, but just imagine how many k's we could get out of these motors if they run cooler??
Anyway I will keep in touch with any info I come across regarding this topic and I hope to see you soon (in Birdsville ? ).
Regards Trevor.