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Running hot, what do you think?

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ZenkaiRacerDsM

20+ Year Contributor
760
7
Nov 8, 2002
Layton, Utah
So now that the weather is warming up my car is running hot all of a sudden. Didn't have a problem with it last year and I haven't changed anything. Its really not even hot yet and its damn near overheating.

Alright so heres what its doing. Whenever I'm at a stop light for a little bit the needle will go from its normal spot of a tad under the middle to a little over 3/4 of the gauge. Then the fan will turn on and it will return to its normal spot. If I continue to idle it will keep doing this cycle over and over. Why isn't my fan coming on before shit gets really hot? Sometimes even while I'm driving it will be higher then normal.

One thing to mention is that if I run my A/C the temp will hold at the normal level no matter what. Its solid. Once I turn the A/C off its right back to the hot/fan cycle.

I'm thinking that the low speed setting on my main fan is dead. And the high speed only comes on when it gets really hot. Which is why the fan wont come on at all until the gauge is 3/4 and above.

What do you think? Should I buy a new fan? I'm installing a two core aluminum radiator this weekend.
 
When is the last time you changed your coolant? What mixture did you use?
Start simple.

The gauge in the cluster is completely inaccurate. 1/16" of sweep on mine was the difference of 15-25*F.
You need to look at a datalogger to accurately see what is going on.
The gauge temp sensor could be going faulty, corroded wires, loose/dirty connection etc.

High speed only comes on when A/C is turned on, hence why you don't overheat.
2Gs control the fans via ecu, so some 2G gurus can jump in on this is they like. (I believe high kicks on >220*F)

Food for thought here, but our cooling system should release air pockets over time - however you may have one big good one trapped. Open the radiator cap cold and warm up the car, it's great if you have one of those spill free funnels to top it off a little and see if any bubbles come out - not only that but makes filling a piece of cake.

P.S. You've been on the site a while, how many overheating threads are there? Tisk, Tisk. Search button.
 
Have you checked your coolant level in the radiator? It might just be low on coolant. That would explain why it will start to creep up until the fan kicks on and then it is able to bring the temp back down. It would also explain why it doesn't do it when the a/c is on, because the fans run/cycle more often with a/c. You better check it before it's too late.
 
Already checked the coolant level. Replaced the thermostat since I've never replaced it and also bled the air afterwards.

Didn't do a coolant flush yet though. Only drained what I needed to drain to do the thermostat since I did it in my apartment parking space. Will flush it all when I do the radiator this weekend though.

I did not do a search because I was more wondering about how the main fan kicks on on a 2g. And if my hypothesis is correct. I know all about the search seeing as I have 356 posts in all the years Ive been on here.
 
Already checked the coolant level. Replaced the thermostat since I've never replaced it and also bled the air afterwards.

Didn't do a coolant flush yet though. Only drained what I needed to drain to do the thermostat since I did it in my apartment parking space. Will flush it all when I do the radiator this weekend though.

I did not do a search because I was more wondering about how the main fan kicks on on a 2g. And if my hypothesis is correct. I know all about the search seeing as I have 356 posts in all the years Ive been on here.

Relax, it was not an insult, perhaps I'll use italics to make you not so upset.
I have 680 posts in 4 years. Did I make a point or a state a fact there?

Here are some good starting/reference points.
Enter ECU Learn Mode :: 180F (82C)
Coolant Fan ON :: 210F (99C)
Pull 1 degree timing :: 206F (97C)
Pull 2 degree timing :: 224F (107C)
Enter Open Loop Mode :: 228F (109C)
Default Coolant CEL :: 235F (113C)
A/C Override :: 240F (115C)


http://www.dsmtuners.com/forums/newbie-forum/234008-my-cooling-fans-kicking-too-late.html

Fan controller...something to think about if its that bad.
Derale Deluxe Adjustable Controllers with Pipe Threaded Probes Fan Control - Thermostatic - Adjustable - 150 Degrees On - 240 Degrees Off - Kit | StreetPerformance.com

Good thread on ecu pinouts and what to look for.
http://www.dsmtuners.com/forums/newbie-forum/234045-cooling-fans-issue.html

So basically you have to start diagnosing. Getting some test results...then diagnose if you really have an issue and where/ how to isolate it.
 
Thanks for the info man. Tomorrow I'll see what link says the temp is at relative to what the stock gauge is showing. Also to see what temp the fan is actually kicking on at.

I'm just so used to it being rock solid all the time. Its only ever moved above normal once in all the years Ive had it, and that was when a line popped off and it lost coolant.

Looks like its not as bad as I thought. Still hot to me though.

After the car is warmed up the temp bounces from 203° to 213°. The fan kicks on when its supposed to at 210°.

Guess Ill see how she runs when I swap the radiator and flush the fluid. I'll run a higher water to coolant ratio with watter wetter. Also install the 1.3 bar cap when it comes in.
 
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