Tw3NTy0n3

iTrader: (1)

I'll try to keep it short. Edit: I tried!!

From a cold start, I cannot get the car to overheat when stationary. I can rev it and leave it on for an hour, it simply does not overheat.

On a warm day, after warming up, I take it for a drive (10 min) and when I come to a stop, it will start to overheat. When it starts overheating my RPMs climb as the coolant temperature climbs.

Example: Coolant temp at 210, RPMs at a steady 1100, Coolant temp at 220, RPMs are at a steady 1600, etc.. I can cool the car off by driving it but as soon as I come back to a stop, the temperature rises again.

Fan kicks on at 204 just fine.

Some history:
Last year my car would randomly overheat. I could never get it to overheat on purpose and neither could two separate car shops. Driving it on the freeway would cool it down or just pulling over and waiting. Then it would be fine after that. It would happen once very other month or so.

This year:
Car overheated, needle in the red!
Warped head
Resurfaced head
Put the car back together, runs great minus the overheating issue explained above.

What I've tried:
New Thermostat
New Fan
New Fan Control Module
Water pump is roughly 40k miles old
Bled the coolant system for air
Paid to get the coolant system tested and bled for air. Flow is good according to them, no coolant leaks.
There isn't any type of smoke coming from the exhaust

Any ideas as to what I can try next besides replacing the water pump? I almost want to leave that as a last item since the flow tested good.

Questions:
Anyone know what temperatures cause the fan to kick into a higher speed? I haven't let it get above 220 and at that temp the fan looks like it's still on the same speed as it was when it kicked on at 204.

Can it be that the bottom block is slightly warped and when I drive it, some air gets into the coolant system introducing air bubbles causing the overheating issue when I drive? I haven't been able to find a exhaust fume testing kit for the coolant system local to me so I'd like to get some feedback on this before making a decision to order one online.

Thanks in advance!

RalliartN

iTrader: (1)

You didn't mention checking the coolant temp sensor and/or gauge for proper operation. Do you have an aftermarket coolant temp gauge? Is it just a gauge reading that makes you think the engine is overheating?

Tw3NTy0n3

iTrader: (1)

I'm reading the coolant temperature using the ELM237 OBDII Bluetooth Adapter and the Torque app on my phone.

I would assume it's working since on a cold start when it's idling and reaches 204 degrees, the fan kicks on and cools it back down and the temp drops. When I drive it around to get it to overheat, at 204 the fan kicks on but the temp/RPMs keep climbing.

I assumed the senor would be working based on the above info. I also would assume that it would throw a code if the sensor was broken.

bakuro117

iTrader: (5)

this sounds dumb but its late and im reaching for options here.

Have you flushed the coolant system? they make stuff you can put in and run for a bit to clean it out. fill and flush a few times and your might pull some gunk and build up out of there.

Have you tried running just water instead of coolant mix? if so does it act the same?

Tw3NTy0n3

iTrader: (1)

Yeah, I've flushed it myself about 3 times. Once when I replaced the thermostat, again when I mounted the new fan and again just now when I removed the thermostat. I also had it professionally flushed and tested for proper flow.

I haven't tried just water.

Tw3NTy0n3

iTrader: (1)

Today, I removed the thermostat and removed the radiator cap and started the car.

I expected to see the coolant flowing from right to left like a creek and I expected it to look more like a river when I revved the motor.

The coolant just sat there! I revved the motor and it looked like it wanted to start moving from right to left. I saw a little bit of miniature waves pushing from right to left when I revved the motor but it wasn't really flowing.

Am I missing something? Even at warmed up temperatures (190 degrees) it behaved the same way.

1. Is our water pump the clutch type where it engages at a certain temperature? I was under the impression it was always on/flowing and the thermostat is what opens to let the water through at 170-180 degrees.
2. What temperatures would be deemed safe operating temperatures? I've only let it get up to 220 before shutting it off. I was thinking of maybe letting it get a bit higher and hoping the fan kicks on at a higher speed and cools it all the way back down. Too scared to let it get hot as I did all the work myself when it overheated, I'd hate to do it all again.
3. Any ideas on the weird RPM/Temperature rising together? I took some pics of it this time. I wasn't touching the accelerator at all.
Temp / RPM Rise

Mobsters

(partially)Blocked radiator? rust deposit inside radiator?

i think rpm rise together with temp is car trying to save itself, more rpm, more coolant flow as waterpump should be always turning.

Tw3NTy0n3

iTrader: (1)

Sorry, I forgot to mention that it's a brand new radiator. That was the first thing I replaced since the old one was cracked. It's all aluminum, a bit thicker but I was able to make it fit.

Yeah, the rpm rising to save itself sounds logical. I had thought about that too but I wasn't able to find anything on google to confirm that behavior.

stayer

The reason for the reduced pulley size. I wrote on the forum 4G. Argued with me Mike (RRM) http://club4g.org/board/4g-eclipse-g...ft-pulley.html Read the comments to this thread. I don't want to say anything bad about his products. But this causes reduced rotation of the water pump. Poor circulation of coolant.

stayer

created a thread in evom
https://www.evolutionm.net/forums/04...lley-4g69.html

Tw3NTy0n3

iTrader: (1)

Thank you for sharing that. Very interesting read. I never had this issue before and the pulley is the very first mod I did to my car around 9 years ago. This just started happening last year every other month. This year it's doing it every single day.

stayer

It is not immediately. The walls of the cylinder gradually silting. Further, this process will only accelerate.

CrAnSwIcK

iTrader: (5)

I've never liked the idea of an underdrive pulley...if that is the cause of your overheating, that would be very interesting...I never would have thought about that...I knew they were gimmicks, but I would have thought in a million years it would cause problems other than the obvious dim headlights, less power steering force etc.

Tw3NTy0n3

iTrader: (1)

Just to update this.. I replaced the coolant temperature sensor. After some extensive night time driving it started to behave the same way. To really test/reproduce the issue I will have to test during the day when it's hot.