Engine running hot, looking for opinions - Updated

[skid542]

I spent today at a snow rally-X, what a freakin' blast , but now my car's running hot. I've noticed it running warm, 2*-3*, the past couple of weeks but now it's hot - not overheating but hotter than normal.

The weather is about 13*F, so keep that in mind.

Idle it warms up to an even 194* and sits steady. Normally it's at 183*. Once I start moving it drops back down a little bit.

Driving down the interstate at 60mph, it floats between 185*-189*. Normally it's around 181*-183*.

Engine seems to be running fine, strong, no hesitation. The O2 sensor is showing it being a little richer than normal. This is with the stock narrow band but with Vikash's graphical tool it's definately richer than usual. This is a full throttle.

Exhaust doesn't have a distinct sweet smell. Has a little fuel smell but it doesn't smell sweet.

The coolant appears to be a normal color though I will check again tomorrow after it has cooled off and cycled some coolant through to the overflow bottle and I can open the resovior cap.

I don't know if this is relevant but - about two weeks ago I'm driving home from work and sitting at a stop light I hear a change in the exhaust note. I look down and the idle has dropped to 625-650 from the usual 700. I get home, leave the car for about 10 min. and come back out to run an errand and it wouldn't start after about a 10 min. sit. It'd fire then immediately die, like it wasn't getting fuel. The next day it started right up with no problems.

This idle thing has happened a couple of other times, including tonight. I don't have to get it any gas or anything to keep it running, it just slows the idle.

I'm not sure if the idle is related but I am definately concerned that in 13* weather the engine idles at a stop light at 194*. This just doesn't seem right.

Right now I'm thinking thermostat. Well allow me to rephrase that - I'm hoping it's the thermostat and not a HG. I've tried being easy on the engine, let it warm up before gassing it. I drive only about 5 mi. to work and the last turn before I get to the parking lot the engine coolant temp is 183* and I'll string out first. Before then I'm taking it easy.

Also, I'm only running 11-12 psi boost.


Any opinions or comments?

[ericem]

As long as it is not using coolant and the coolant oil colour's are normal I would not worry about the headgasket. Just replace the rad cap(or turbo car's dont have one ? ) replace the fluid with subaru fluid, and get the thermostat and gasket for the thermostat. It is not much higher realistically.

[Legacy777]

Thermostat or possibly radiator would be my first likely suggestions.

[skid542]

I'll start with the thermostat and a new cap. I'll swing by the dealer this week.

I'm thinking the radiator should be fine, it's only about a year old. But if the thermostat and cap don't take care of the issue I'll swap in my spare - I don't like to because of the AT cooler and associated mess .

Thanks for the input guys. I had a little bit of a knee jerk reaction as last time it got hot I had to do HG's in the winter in an un-heated garage.....

[Buffman]

maybe different on a subaru t-stat, but in any application I've run by all T-stats usually are fully open 20* higher than what they're rated for.


do a Compression Test.

[evolutionmovement]

Could be the coolant sensor maybe, too.

[jefferson]

Maybe you packed your radiator full of snow. Been known to happen.

[skid542]

Thanks for all the continued input, much appreciated.

Buffman, would I lose credability as a man if I said I was afraid to pull a plug and see what looms underneath... . A compression check is a good idea though, I'm just afraid as I really don't want to spend another winter doing HG's in the evenings after work in my 10*F garage.

Steve, I'm pretty sure the sensors are right. The dash gauge was reading high and the ECU gauge was also high. It seems unlikely that they both failed concurrently.

Jefferson, this is true and had occured to me. On the way home I stopped at a DIY carwash and washed out the snow from the wheels, wheel wells, undercarriage, and sprayed a bit right into the radiator. I would have thought that would have cleared any snow in the radiator but it still idled hot on the way home. I guess there could have still been snow in there but I gave it a good 30 sec. sweeping with the high pressure spray right into the grill. On a side note, the steam was wicked looking in the cold dry air as water hit a hot radiator .

Right now I think the current plan is to do a compression later this week. Assuming that all checks out I'll stop at the dealer for a new cap and thermostat.

Any more idea/comments are welcome and I'll keep posted on my findings.

Thanks.

[evolutionmovement]

I meant the sensor for the ECU, but I somehow confused myself so never mind. I was thinking with your rich-running the sensor might be kicking it into a safe mode, but if you're running hot, that's exactly what the hell it should be doing. Stupid brain.

[Legacy777]

Look between the condensor & radiator......if it's very cold, you may still have an issue. You really need a garage with a heater going over night to let it thaw out.

[skid542]

Time for a quick update -

I spent today working on the SS to get her back out on the road and ready for the upcoming swap.

First step was compression test - 142, 145, 148, 145.

Next step was the thermostat, swapped it out for a brand new one from the dealer.

Results - still idling warm, high 180's, low 190's. On the road it's holding a steady 183-185. I drove probably around 15 miles. Got onto boost as much as I could, no problems there. Temps would drop and then come back up.

I'm still no happy with the higher than normal idle temps. I didn't put a rad cap on - should have - but I'm thinking of just swapping it with the one on my OBW (0.9 bar) and seeing if that makes any difference. If so, I'll get a new one to throw on.

I'm still open to thoughts if anyone has any.

[Matt Monson]

When you replaced the radiator did you go with one with a cap on it? If so, you want to be sure that you have your radiator and turbo coolant tank configured in a particular way.

You want a 0.9Bar caps on the coolant tank and a 1.1Bar cap on the radiator. Call it an order of operations thing. If you don't set it up that way, it will run hot.

[skid542]

Thanks Matt. The replacement radiator is like the stock radiator. The only cap in the system is on the coolant tank. I will keep that in mind for future reference though - thanks.

[Legacy777]

Lee,

Those temps are pretty much normal.

The stock ECU regulates coolant temperature between 190 & 200 deg F.

The thermostat shouldn't let the coolant drop below the mid to low 180's.

[skid542]

I know. And I realize I'm probably chasing something that's not worth chasing. However, it still just strikes me as odd that prior to the last rally-cross it was running several degrees cooler. In the summer time I'd see it get up to 205*F and the fans kick on, but in the winter it's used to run a little cooler. It was pretty uncommon for it to hit 190*F when it's only 15*F outside and now it'll hit it just waiting at a stop light.

I'm still going to swap rad caps just to see if it makes a difference. And if it doesn't, I'll just let it ride and see what happens as the weather outside continues to get warmer.

My baby's got a small fever and it's stressing me out ....

I do really appreciate everyone being patient with me though and providing input.