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Q32 Overheating

Posted: Sat Apr 19, 2014 9:03 pm
by lockedlock
I have a 1990 Terrano auto with some overheating issues.
It has a reconditioned Q32 Diesel, brand new radiator (after market but same dimensions as standard Q32 came with).
I have replaced the electric fan it had with a new vicus pump/fan and shroud. Replaced the pod filter it had directly to the turbo with the standard air box, and added a transmission cooler in front of the radiator.
I havent had it over heat on me since doing all that cooling system work on it, but it still runs very warm when under load for example, driving up the kaimais (on the road) I want to get the temperature to stabilize instead of fluctuate between running well under warm with general driving, to almost boiling when driving up long hills on road.
If it helps it does have a 2inch body/suspension lift and 31" muds. Not that they should make a difference.

I do have an intercooler which i could fit and maybe put the electric i pulled off, and turn it into a push fan to aid the flow of air.
Has anyone had any experience with this engine/truck combo or any suggestions would be appreciated.

Re: Q32 Overheating

Posted: Sat Apr 19, 2014 9:41 pm
by slidenyo
if you mean qd32,
mate has one ,
big exhaust , correct thermostat and keeping it in 4th (manual) when towing is all he's done
auto would be much the same advice keep it in a lower gear when towing/kaimais.
your symptoms to me though point towards faulty or wrong thermostat selection or a shit temp gauge.
maybe its time for a decent aftermarket gauge to go in and tell you the real temp?

Re: Q32 Overheating

Posted: Fri Apr 25, 2014 5:17 pm
by lockedlock
Yeah QD32. OK thanks for that. Im aware some after market thermostates can be crap so i have a brand new one from Nissan so should be sweet with that.
Ill put in my after market gauge and see what it reads at, also this week im going to have a play with the fuel pump, think whoever put in the big turbo just cranked the pump up to match the turb?

Re: Q32 Overheating

Posted: Sat Apr 26, 2014 4:04 pm
by slidenyo
well an egt gauge sounds like it should be there too,
mates truck runs a td27 turbo and manifold with the pump wound a bit and it runs itself out of diesel around about 3 grand with an open exhaust more fuel and it would just be smokey as all hell and get to hot.
what revs are you pulling to achieve the most pull?
the turbo could be a mismatch to the engine quite easily

Re: Q32 Overheating

Posted: Sat Apr 26, 2014 7:41 pm
by elvis
Hey mate do you have an aftermarket bulbar on your truck? i used to have overheating problems with mine till i drilled a few holes in bar to help with airflow-i took front bar of to test it and couldn't believe the difference.
good luck cheers troy

Re: Q32 Overheating

Posted: Sun Apr 27, 2014 12:17 am
by lockedlock
Thanks for all the feedback.
I dont have a bar on there currently but am looking at it for the future with a winch. Today i put the electric fan back onto the front of the radiator to act as a push and wired up an aftermarket temp gauge so will keep an eye on it and see how it reads this week.

As for what revs does it pull best, im not sure. The factory counter hasnt worked since i bought it. I have an autogauge tacho from my escort, could i use this? Or do you need to buy a diesel tac?

Re: Q32 Overheating

Posted: Sun Apr 27, 2014 10:00 pm
by ChurchurDan
You need a specific diesel tach, or a signal converter to run the autogauge tach. The converters tend to be a little crude and don't offer enough accuracy.

Re: Q32 Overheating

Posted: Sat May 03, 2014 3:59 pm
by kiwinoz
I started running cooler....odd here.
Even with aircon on, now and then it would be down at about 1/4 rather than usual 1/2.
Was a build up of crudd (higher resistance ?) in the connector to the temp sensor.
Cleaned, lubed, sits around 1/2 all day now, no matter what Im doing. air on/off 4lo.

So, dodgee sensor or gauge could be your problem, even an earth problem will fk things up.

Re: Q32 Overheating

Posted: Sat May 03, 2014 8:02 pm
by lockedlock
Yeah i do run under 1/2 way aswell on the factory gauge.
I just installed an aftermarket high flow thermostat and a temp gauge that has the actual degrees on it. So far not over heating with towing around town and normal driving. and seems to run between 70-75 which is good i think. Have also sourced an 4x4 radiator which is 50mm instead of my 32mm one which if it still over heats i will get.

Re: Q32 Overheating

Posted: Sat Jun 28, 2014 12:30 am
by lockedlock
Had no luck with only changing the thermostat, so just bought a heavy duty radiator from Turbo Desiel Speacialist Hamilton. Cost me an arm and leg. Its got about 10mm on the factory one, and is made of brass? Or copper? Not sure but one of the guys from the shop says he runs the same thing in his terrano QD32.

Installed it and took it for a blast straight up the Kaimais.
Before this radiator i would be running at 75 degrees then by the time reaching the top would be near boiling at aroung 97.

With this radiator i was also starting at 75 but it held at 85 for the whole hill.. Which on the factory temp gauge is half way between warm and hot.
Was kinda expecting it to hold temperature a bit better after all the changes ive done but i'm now all out of ideas.

It definitely didnt over heat but just wanted to know if this is alright for the truck? Or if anyone else has a 90's Terrano with the QD32 in it and similar temps?

Re: Q32 Overheating

Posted: Sat Jun 28, 2014 1:12 am
by Crash bandicoot
You have to remember that 100° on a pressurised system isnt boiling point. As for the bullbar go with the split pan design. Will help with the air flow 85 up thekaimais is good.

Re: Q32 Overheating

Posted: Sun Jun 29, 2014 10:43 pm
by lockedlock
Sweet as, yeah i just wanted to be sure. So pretty happy with it now. Going hard haha. Am going to leave the bull bar for a while yet, just did a home job snorkel though, looks and works the part. Will put up a picture tomorrow

Re: Q32 Overheating

Posted: Mon Jun 30, 2014 10:00 am
by stovanovich
As mentioned above by Crash 100deg aint boiling point. Take a look at your aftermarket gauge as a lot of them have a warning section on them (generally red) that's when things are getting hot. My 92 with a TD27Ti runs much the same temps up the kaimais as you. Drive smartly to both gauges and you'll be right. An EGT will also be a helpful piece of equipment going forward if you wanna be double safe and temp is a worry :D

Re: Q32 Overheating

Posted: Mon Jun 30, 2014 8:06 pm
by slidenyo
big brass copper radiator won't see you wrong mine was $820 for the safari,
cheap insurance I reckon,
running up to a 100 is fine as long as your system is fully bled and the fans are working when needed