Overcooling? Cooling gurus needed.

[zachattack_5491]

I live in the dessert where temperatures have been reaching 100+, and I've somehow been overcooling according to my stock gauge. This is going to be a lengthy post, so you better put your reading glasses on

This all started during a two hour highway drive back home. My setup was 2 core aluminum radiator, stock shroud, stock thermostat, stock fan, 25% coolant and 75% water. It was about 70 degrees outside at 3am. After an hour of my drive I stopped to get some food and checked on the status of my engine. The bay was pretty hot, along with the engine. The upper hose of my radiator was very hot, and the lower was cold. So I figured maybe the thermostat was stuck closed. I found that very odd because my temperature gauge was completely normal. I don't think it's broken because I've seen it move to the very hot side.

So I get home and pull the thermostat out. I decided to run no thermostat until my Mishimoto one came in the mail. During the 3 days with no thermostat it was a struggle to get up to operating temperature. It always stayed between the first and second line until about an hour into driving. I cut a piece of cardboard up and blocked about 1/4 of the radiator which helped a bit.

I installed my new cooler thermostat, and it's still acting very weird. Now it warms up at little faster, but still hangs abnormally low on the gauge.

Running a bit cooler doesn't bother me. It does bother me that the ECU dumps more fuel, ups oil pressure, and changes the timing while I'm driving around town because it thinks it's freezing. Also, my car drives VERY poorly until it gets up to the third (normal) line on the gauge. It feels like it's holding back until I get to a certain amount of throttle and then boom it lets loose. Very weird. Does anyone else's drive similar to mine or should I look into that?

So what I'm thinking is that maybe coolant is not fully travelling throughout the engine. If you look at the diagram of the coolant flow in the FSM, it's pretty random. Could it be possible that one of these paths is clogged, and therefore not absorbing heat from the engine? I guess I'll replace the water pump just to be on the safe side. By the way, my heater is HOT! Like crazy hot, at least it seems like it coming from my KA. I would think it's very abnormal but my friend's RB20 is about the same. Anyone have any ideas? I'm going to order a new water pump, and both temp sensors and see if that helps anything.

[almost heaven]

Not a guru, but, have you baselined your temp sensor? Maybe it's bad.

[DuckyD]

If your engine is warm but the radiaator is cool, you may have a blockage in coolant flow.
Be sure to properly bleed the coolant (some people have better luck raising the front of the car) and that your waterpump isn't toast.

[PyR0NiAk]

Mishimoto thermostat is a 60 degree Celcius thermostat... That transmission to 140 Fahrenheit.

[zachattack_5491]

If your engine is warm but the radiaator is cool, you may have a blockage in coolant flow.
Be sure to properly bleed the coolant (some people have better luck raising the front of the car) and that your waterpump isn't toast.

I'm pretty sure I bled out all the air like a champ. Usually even when I don't do a good job, after a few days of driving and topping off coolant it works itself out. My driveway is tilted up at a pretty good angle.

Mishimoto thermostat is a 60 degree Celcius thermostat... That transmission to 140 Fahrenheit.

Yeah, I know I should be running cooler thanks the the thermostat. But it's still lower on the gauge than it should be. Stock is 172 if I remember correctly. Does anyone have any input on how the engine runs when the gauge is anywhere below the normal line?

Not a guru, but, have you baselined your temp sensor? Maybe it's bad.

I have not tested them. I think I'm going to put the old ones from my KA in there (not sure the ECU sensor is the same yet) and see how it runs.

[PyR0NiAk]

Every SR I've seen with the mishimoto thermostat runs pretty cold.. Think about it. That's more than 30 degrees less than the stock thermostat.

[nissan_star]

I am pretty sure my buddy fried his SR because of a similar problem you have, his temp said it was right in the middle not too low like you. In his bay it seemed unusually hot though, like super hot even. Not positive what actually caused it, but you better watch it.

For clarification: Does having a low temp thermostat actually make a car run cooler? Or if you car has a problem cooling, like a small radiator can't keep up, shouldn't it keep overheating?

[zachattack_5491]

Well that doesn't make me feel any better. I'm already paranoid as it is without hearing similar stories of people blowing engines.

The thermostat just opens at a cooler temp so it tends to keep the engine a little cooler. If the rad can't keep up, it won't really help.

[nissan_star]

I don't know what to say, you have reached the end of my knowledge.

flush the coolant and look for suspicious characters.? i don't know dude, but keep us updated.

[PyR0NiAk]

flush the coolant and look for suspicious characters.

I was thinking the exact same thing..