Over heating issue

[Youssef]

Ok guys I was a bit hesitant to post as I didn't want to ask something that was already asked, but after a few days worth of searching I am ready to consult the gurus of the VR4. So here is the scenario
The car is a 97 Galant Vr-4 5 speed auto. List of mods are small but include exhaust, FMIC and EBC (15psi or 1.03 Bar).
I was driving the car a bit "enthusiastically" the other day (was really hot outside I would say somewhere in the area of 38 degrees of so, Caribbean weather) going up a pretty steep hill when the car started to overheat and spit out water. I should also point out the ac was on. So I pulled over and within a couple minutes the temperature returned to normal without me even shutting off the car. So I continued driving at a much slower pace and topped it up with water when I got where I was going. Within 30 minutes or so of this I was driving up yet another steep hill, this time still going slow with the ac on and the car over heated again. Pulled over and within a few minutes back to normal. No water came out this time. Since then it has not overheated but I have been avoiding long steep hills and any spirited driving has been done with the ac off. I checked for leaks and found none, I don't think it's the Head gasket as I am not seeing any oil in the coolant and there is no extra pressure in the Radiator when I rev the engine with the cap off. I have not checked the thermostat yet will do that over the weekend but someone who I have alot of faith and confidence in says his gut is telling him the problem might be oil related. There is a dent in the oil sump so maybe the pick up is being obstructed. I do have an oil pressure guage installed and it's giving me the following readings:
Cold Idle - close to 50 psi (3.45 Bar)
Warm Idle - Close to 20 psi (1.38 Bar)
Particial Throttle operating Temp - close to 30 psi (2.07 Bar)
WOT operating temp - close to 44 psi (3.03 Bar)

Can Anyone give me an idea if these are normal readings or if it is low. I really want to rule out as much possibilities before i start probing deeper. Can lower oil pressure produce a situation as described above. What can possibly produce the above mentioned situation. Any insight will be greatly appreciated, thanks guys and sorry for the long post I am just trying to give as much info as possible.

[Wodjno]

Hmmmm ?Hmmm

Bit of a strange 1 your right about that /yes Not 1 i've heard of before, but also not used to those kind of Temps here in the UK :(

But it does sound like it could possibly be that your Gearbox is being overworked with the load and heat added together ? As the gearbox cooler is attached to the underneath of the radiator, it could be getting very hot and then transferring heat to your radiator. Thus overheating your already hot water in ther cooling system.
I have had this on Spirited Track driving /yes This would be as close to the sort of heat and load as i could get over here ?

Sure someone else will be along soon with other ideas /yes

Cheers

Wodj

PS.. If this is the issue, then a remote gearbox oilcooler would be the way to go.. And it is a very good modification for Autobox longevity from the start ...

[Longbow77]

From a general viewpoint, at 15psi you might not have sufficient enrichment to keep the engine cool under full load. Also, with the stock intercooler might be becoming heatsoaked and therefore you'll run leaner leading to higher combustion temps. If you're going up very steep hills, I doubt you'll have the speed up to ensure that the radiator and/or intercooler is receiving enough airflow. In all cases you're looking at potential serious engine damage.

As a simple fix to all of the above - water injection system e.g. Aquamist.

[Turbo_Steve]

Er...until it runs out of water, and then you're back to engine damage: unless you're going to control the Aquamist with temperature AND load parameters, it's not something I'd want to rely on.

I agree that you should perhaps check your AFRs if the engine is going to be running sustained heavy loads in high temps, though your oil pressure is likely to tell you when the engines getting really really hot.

I reckon Wodj is pretty much on the money - you're running higher boost and just getting the whole thing too hot. Chances are that your steam was coming through the expansion bottle vent.

Experience over here has shown that the gearbox cooling is barely adequate: For the small sum it costs to fit an uprated cooler, I would STRONGLY reccomend it in your climate. Mount it behind the foglight to ensure it doesn't block airflow into the radiator.

Your uprated intercooler would appear to be an excellent investment. As a safety precaution, you could create an "over temperature" spray for it.
At it's simplest, this could simply be an additional water tank, a screenwash pump and an atomiser nozzle connected to a thermostatic switch on the intercooler exit. Once the temperature goes over 30degrees, you can douse the intercooler in water, which should help to control temperatures.

I'd reccomend an oil temperature gauge at some point.

Long term, I suspect you should be budgeting for an uprated ECU.
A remapped ECU or good piggyback will give you power gains accross the range, protect you from leanness and det and allow you to run on your local fuel without worry.

[Youssef]

Thanks for the quick responses guys, I do have an uprated IC on and when I over heated on the second occasion i was barely hitting 3 psi, I turned off the boost controller and was running stock spring pressure after the first time it happened. I had initially suspected the combination of the external heat and the raised boost as the problem. Could it be the second overheat was simply a residual effect of the first instance. Also why did the temp go back down so quickly once I stopped. I do intend on getting a cooler for the tranny as I have experiences with auto tranny failures in the past and I know the excessive hills and temps we have down here really puts a toll on Mitsubishi already sensitive Autoboxes.
An IC sprayer while it will be useful I think is a bandaide and I would rather come up with the underlying cause of the issue. I did check my AFR's when I was running 10 psi and hit as high as 11.4 at cruising and as high as 10.3 at WOT. I used a Wideband with a tailpipe sniffer so I would make some small adjustments for that but if anything the resulting AFR reading would be learner than it actually is.
Could a sticky thermostat cause issues like that?

[AlanDITD]

From a general viewpoint, at 15psi you might not have sufficient enrichment to keep the engine cool under full load. Also, with the stock intercooler might be becoming heatsoaked and therefore you'll run leaner leading to higher combustion temps. If you're going up very steep hills, I doubt you'll have the speed up to ensure that the radiator and/or intercooler is receiving enough airflow. In all cases you're looking at potential serious engine damage.

As a simple fix to all of the above - water injection system e.g. Aquamist.

Since when was water injection a solution to an overheating problem?

edited you alrady have done some of the things i was going to suggest!

[Rambaud]

I assume you are using at least 98 RON petrol?

If not, this might be contributing to the higher temps. Plus having the air-con on also.

[Turbo_Steve]

It does sound like you have a coolant problem: I'd suggest there is, perhaps, air in the system? As you go up hill, the air will rise to the "top" of the car, the highest point, which will be the radiator top hose?

[Youssef]

But if it's an airlock problem shouldn't it happen anytime I climb a hill and trust me in Grenada there are ALOT of hills. Either way I will continue to observe it and see if I can recreate the issue. Can you guys still tell me if the oil pressure readings I mentioned in the original post is good or if they are below normal?

[elnevio]

Your idle pressures look spot on to me. I would have thought the WOT pressure would have been higher? Perhaps the more-enlightened ones will advise.