2G Higher Temp

spyderdrifter · Sep 3, 2017

Yesterday morning I stopped to get donuts after work, and while I was waiting, I happened to notice my temp gauge was nearing 3/4 up the gauge. I turned on the a/c and the needle went back down to normal. I decided to plug my scanner in to see if there was high ECT being logged, and it was at 210. So I drove the couple miles home going easy on the car. Once I parked, I shut off the a/c to see how high the temp would go and it reached 219, and dropped back down to the comfortable 206 when I put the a/c back on. This is the first time this car has had temps over 206 since I've owned it. Is there anything besides low coolant, bad t-stat, or faulty sensors that could contribute to this? I know the most obvious would be the water pump, but looking for other options to try out first. I do have a P0170 code that pops up at least every other day, and have had a P0125 once. I'm convinced both are because of a bad o2 sensor, which I got a new one to put on later today. I don't think there are any boost leaks. I've had leaks and idle surge on past DSMs, and this one runs smooth and has a very steady idle that ranges from 750-760rpms when in park, and right around 800rpms in drive but stopped. Anyway, just looking for ideas.

SOADweskey · Sep 3, 2017

Sounds like the passenger side fan isn't flowing air like it should. The AC on should make the problem worse as it adds more heat in front of the radiator. But the drivers side fan kicking on with the AC must be what is helping you out.

iceguru1114 · Sep 3, 2017

If you have a bad O2 sensor, closed loop trim at low load might not be working correctly. Usually when that's the case, the ECU defaults to running rich and, depending on some other variables, like ignition timing, that can make the in cylinder temps a little warmer which will, in turn, increase coolant temps.

Also, although any change in engine performance out of the ordinary should raise some eyebrows, 220F isn't quite enough to be concerned that you're going to damage something.

spyderdrifter · Sep 4, 2017

SOADweskey said:
Sounds like the passenger side fan isn't flowing air like it should. The AC on should make the problem worse as it adds more heat in front of the radiator. But the drivers side fan kicking on with the AC must be what is helping you out.

I somewhat thought about this, but since I know it cycles on and off at regular intervals, I'm not sure how I could check flow. Not sure why the a/c fan coming on should be bad. I've done that before on my old spyder and it always made the temps drop a bit. I have stock fans so they would be pulling the air through the radiator and a/c condenser instead of trapping it in front of it all.

iceguru1114 said:
If you have a bad O2 sensor, closed loop trim at low load might not be working correctly. Usually when that's the case, the ECU defaults to running rich and, depending on some other variables, like ignition timing, that can make the in cylinder temps a little warmer which will, in turn, increase coolant temps.

Also, although any change in engine performance out of the ordinary should raise some eyebrows, 220F isn't quite enough to be concerned that you're going to damage something.

That makes sense, except this is the first time the temps have gone up and I've had the car for a month now and have needed the o2 the entire time. But I am glad that the temps it's reading aren't too alarming. I didn't get my o2 changed out today, so maybe tomorrow.

spyderdrifter · Sep 5, 2017

Little update: I replaced the o2 today (new one is a Bosch sensor) and the car does start and shut off better as well as drives better. No CEL coming on yet, but the ECT is still logging high on my scanner. I will be replacing the t-stat, rad cap, and the sensors (if those are bad) once I get to the point of a coolant flush.

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SOADweskey · Sep 5, 2017

I took a look at the service manual to see if there were any checks that can be done on the fan and there really isn't anything more than apply battery voltage and ensure that the fan spins. This could be beneficial to turn on the fan with the engine off to see if the fan motor is making any abnormal noises. Also I would spin each fan by hand (obviously with the engine off for safety) if the passenger side fan exhibits more resistance to being turned by hand than the driver's side fan does then that may also indicate a problem with the fan motor.

Also as mentioned coolant temps in the 220's aren't unheard of from a DSM. But that is usually when you have removed the awesome stock fans for less awesome slim fans to make room for a bigger turbo.

With the A/C on and in stop and go traffic here in FL I will see 225-230. But I have a VRSF front mount and one good SPAL fan pulling on the passenger side and a generic slim fan pushing on the drivers side.

spyderdrifter · Sep 5, 2017

I'll give that a shot, sounds like something I should have thought about, but I didn't. I had a vrsf fmic on my last dsm (awd spyder), but the big difference was I had removed all the a/c components long before getting the fmic. So when it went on, I never saw all the rising temps that most do when adding the fmic. Then I later realized, I no longer had the a/c condensor blocking air flow. Now I do, but only have the oem smic on it. Thanks for the suggestions though, hopefully I'll get this narrowed down soon .

JaKee003 · Sep 17, 2017

I have a 99 non-turbo thats overheating. A couple days ago i was casually driving and all of a sudden my temp was all the way up. When i propped the hood there was coolant everywhere so i cut the car off. I bought a new radiator and put some new coolant. The car was idling good and the temp was normal but when i went around the block the temp rose all the way up. Car is not leaking or smoking so idk what the problem can be. Any suggestions?

Mauispyder · Sep 17, 2017

The two times I had higher than normal temperatures, I was losing coolant. First time was from pitting on the surface that the radiator cap sits on. A new cap wouldn't fix this. Pits had to be repaired. The second time was small hole in the very old small coolant hoses.

dgdsm · Sep 17, 2017

Trapped air or other cooling system blockage? Do the temps go up only when you're stopped and then go down when you're moving again? If you're only seeing rising temps when you're stopped then that's what would do it. 3/4 though is a long ways for the needle to travel. Just another thing to consider.

spyderdrifter · Sep 18, 2017

Today I checked to see if the pump was pumping coolant through the water neck. It is, so my pump seems to be good (for now). So since the 2 sensors, the radiator cap, and the thermostat are relatively cheap, I'm just gonna buy all new ones, and an oem pump, and just replace it all along with a new timing belt and tensioner. When I checked today, I did add a little coolant and let it run with the cap off for about 5 minutes just in case there was trapped air. So far I haven't seen the needle rise up, so that could have been the issue, but I'm not ready to say it was. The needle was originally rising only when stopped, but this last week it would rise while moving too. However, if I pushed the car a little hard, the needle would stay at normal for a while before rising again.

chrysler kid · Sep 18, 2017

Ok first step

Burp the cooling system.

With the engine cold remove the radiator cap and turn the heater to on, max, set to floor or vent not defrost. Start the car and let the car idle with the heater on and the cap off. When the thermostat gets hot and opens it should release any air bubbles in the system

However! My advice if this condition started randomly is to rent a cooling system pressure tester from your local auto parts store to look for coolant leaks. Screws onto your radiator cap and pump it up to cap pressure (13 psi if I recall correctly) and step back from the car to look for leaks, and listen for gurgling noises from escaping coolant in the system

Typically the heater hoses and the iac hoses get weak and at full pressure hot temperature driving down the road will shoot a small leak and disrupt coolant flow that is only visible at high pressure conditions (i.e. under load from the engine or under pressure from the tester)

spyderdrifter · Sep 19, 2017

Yes, I know how to burp the system and do the pressure test. You are correct with 13psi. I have zero leaks (surprisingly). As of now, if I run the car hard, there's no temp increase, but if I drive it easy, the temp rises. Even while moving, not just when stopped.

dgdsm · Sep 19, 2017

OK so this is a dsm you picked up a month ago. Do you know if the ECU and fans are stock? There might be something in this old thread on another forum that's helpful to you. Also I'm sure you've thought of this so I hesitate to bring it up but .... condition of HG ? It's a stretch from what you described but it's something I would check out on a dsm with unknown recent history. Probably a simple compression test would tell you.

Also if it's been sitting for two years, the cooling system could be full of rust .

spyderdrifter · Sep 20, 2017

Yeah, fans are definitely stock, ECU I'm not sure because I haven't removed it yet. I know it is an eprom, but I think I'm safe to assume it too is oem based on what the previous owner told me about the car, but I still need to remove and open it to be 100% sure. I did think about the fans, but with the a/c off, I can hear the rad fan cycle on and off, and I did watch for that when I first went to see the car before buying it. The rust part however, could be a real possibility and will need to look for that when I do a coolant flush. A compression test is needed so I can check the numbers, but there's no oil in the coolant, or coolant in the oil. Both are clean.

boostdawd · Sep 20, 2017

I agree. Flush the coolant. Burp the system after. Also something to consider is to clean the radiator fins. It's possible u may have something blocking airflow and reducing efficiency. Leaves, insects, trash, etc.

spyderdrifter · Sep 20, 2017

That's true, especially after sitting so long. I'll flush it all, but want to get all the new timing and coolant parts before doing it so I only need to do it once.

802gst · Sep 20, 2017

Just went through this in mine. pin hole led to cap going bad followed by thermostat then water pump. I'm in midst of changing timing belt/water pump.
I do know that my get only has 1 fan and always keeps below half mark even on 100 degrees days. so there's definitely a small hole not letting u pressurize or the obvious things I'm sure your checking.

802gst · Sep 20, 2017

sounds too obvious but look for any pin holes, my 16g coolant line cracked n wore my tired water pump out.

802gst · Sep 20, 2017

sorry for double post didn't load first time.

spyderdrifter · Sep 23, 2017

Quick update to this. Right now it's raining heavily, and my front defroster/heater is pushing air that's barely warm even though the engine is well warmed up since I've been driving. Since the front isn't defrosting enough, I've had to stop at a gas station so I don't wreak. Given the last issues with the temps being higher and now not hot enough to defrost, is this a sign that the thermostat is bad?

linksys42 · Sep 24, 2017

spyderdrifter said:
Quick update to this. Right now it's raining heavily, and my front defroster/heater is pushing air that's barely warm even though the engine is well warmed up since I've been driving. Since the front isn't defrosting enough, I've had to stop at a gas station so I don't wreak. Given the last issues with the temps being higher and now not hot enough to defrost, is this a sign that the thermostat is bad?

Most likely heater core is plugged up or thermostat is bad. Remove thermostat and back flush cooling system and heater core. I'd use some kind of flush additive to break up the scale and grime in the system.

chrysler kid · Sep 25, 2017

Drain coolant, replace thermostat, fill with blue devil coolant flush and 2 gallons of distilled water. Drive like this for about a week then refill with coolant

spyderdrifter · Sep 26, 2017

Decided to monitor things a bit more while driving to work tonight. I stopped at grabbed a burger and before stopping in the drive through line, heater was blowing warm. Not hot, but warm enough. Within 20 seconds of being stopped, it sure enough started blowing cold. Did this at each red light all the way to work. As soon as I started driving again, it would warm back up. Will be getting a new thermostat tomorrow morning. Hopefully this cures the temp gauge fluctuations too.

spyderdrifter · Oct 1, 2017

Quick update: I replaced the thermostat today. Tested the new one in boiling water before working on the car, and it opened like normal at 180°. Swapped the parts and tested the old one just to verify it actually failed. Boiling water got up to 200° and it still wouldn't open, so that is confirmed bad. Got everything bolted back up, filled, burped, and at first, there was still cold air coming through the vents with it on heat. This was all during the burping. After the rad fan cycled twice, I shut it off, put the new rad cap on and went for a test drive. Before even moving the car, the heater was blowing hotter than it's been since I bought it, and still stays hot. So that seems to be resolved as well. The only odd thing, was during the test drive, the ect was still registering between 210° and 217°. So I finished driving, ran a compression test since I hadn't done it yet (there's gonna be another post about that issue), and then went home. Since then, the drive home, and now hours later, the drive to work, the ect is running normal temp, according to the gauge. I didn't have my scanner plugged in for either trip to watch the exact temp. So I'll do that in the morning when I head home.

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