Hi everybody!

Hoping to get some advice on an oil temperature problem I've been having. First and foremost, according to the gauge the car seems to be running a little hot. See picture of car all warmed up:

When the car is cold the gauge actually starts right above the white line, so I would estimate that, when warmed up, the gauge is just a little over the halfway point. I haven't been able to get an actually temp reading yet, but does this look hot, or normal? (i'm new to volvos, and to turbos)

The next problem I have is the car seems to overheat slightly while driving in severe conditions (Mainly long sustained hills and city driving) The gauge will move a little less then halfway where the needle is in the picture and the red line. It wasn't until today I was actually able to see the needle move and it makes a really quick jump up, and even made a really quick jump down back to regular. My suspicion is either a faulty oil temp sensor, or a faulty thermostat. This is what I have checked so far:

-Coolant reservoir is at proper level.
-Coolant looks old, but clean (gonna do a coolant flush anyway)
-Coolant level doesn't really change, exhaust is normal
-No corrosion or leaks on radiator
-No pools or puddles of coolant anywhere
-Cabin heats up as it should, seems to affect needle
-Fan kicks on normally at idle, do not know what temperature though, doesn't seem to matter, car overheats at highway speed.
-Outside temp has been between 30F-70F

What are your guys thoughts? I'm thinking sensor or thermostat, leaning more toward sensor. Am I way off?

Oh btw car is:
1995 Volvo 850 Turbo, ~105k miles (odometer is broken )

 

That looks pretty normal.

There is no oil temp sensor.

There is a coolant temp sensor located just below the thermostat housing and I'm guess you might have a problem with it or you could have a head gasket that is starting to go and pumping combustion gas into the coolant causing voids in the system occasionally.

You would want to make sure you don't see any "crud" at the water line in the coolant reservoir tank.

As for the needles position. 3'O clock is considered normal. If someone took the instrument panel apart it's possible the needle was put back on in a different position. I'm pretty sure mine is a little below the end line.

 

That position is normal, as far as it getting hot, your going to want to do a flush like you said, but go with 50/50 rather than straight coolant. If you can get your hands on motochill it would be even better.

But when you do the coolant flush change the thermostat and sensor just to be safe

 

The possibility of head gasket is low, but still their. If you have a compression tester handy its worth a test. Its maybe a 10 minute job to do, if you can get your hands on one. I'm going to go ahead and make an educated guess that its a sticky thermostat. A new thermostat is about $20-25 and a temp sensor is around $30. Plus new coolant. For under $80 its more than worth it to just replace it all.

As far as temp goes, that's right about where mine sits, without fluctuation.

If price is not an issue I would recommend waterless coolant. It is steep on the pricey side. But the boiling point increases significantly, and the freezing point drops just as much. Along with no water comes no corrosion. And with the much higher boiling point, pressure in the system drops significantly as well. It is not needed, But it is a nice feeling to have this stuff flowing through your car, especially on a HOT day. http://www.evanscooling.com/products/coolants/

Hope this helps. Keep us posted!

 

Hey Sean; seriously and sincerely I appreciate what I've seen of your posts so far, but can't agree with you on the above point.

Actually I was going to suggest to the OP that he ck the coolant strength of his antifreeze now. If too strong (> 50:50 antifreeze to H2O ratio) then the engine will run a bit hotter even though the boiling point will be a bit higher. Increasing the boiling point does nothing to help cool the engine unless you're running the engine near the coolant's boiling point (which you really don't want to do).

Google that product and snake oil. Through that search found this
http://www.hrpworld.com/client_image...pdf_3415_3.pdf

If you want to lower the engine's normal running coolant temperature you can:

1. increase the H20 content; yes, water has a considerably better heat transfer coefficient than ethylene and propylene glycol.
2. lower temp thermostat
3. etc.

 

A 20 year old dash cluster can also be the problem, or old wiring. Plug in a obd-2 reader and get the live data when warm, it should be between 183° and 205°. While idle or harder conditions it may get as high as 216° but at that the fan comes on. I have never seen mine get above 218°.

If you use the proper 50/50 mix you should never see corrosion. As that goes, just stay away from tap water and use the proper type of coolant if you can.

 

I completely agree, but the boiling point being raised idea got me interested because I have had a lot of problems with project cars getting hot sitting at a stop light for too long. And when it gets hot, it creates pressure as it reaches or exceeds the boiling point, then boom goes a coolant hose and all the coolant runs out....then your really in a pickle. Let alone the fact that spraying coolant on the exhaust makes a lot of smoke. and you get plenty of looks lol. Using this water less stuff Eliminates most of the pressure. Not to be confused with running cooler with a higher boiling point. I apologize for any confusion I may have caused.

I have seen a lot of corrosion on water pumps and what not. Especially if you flush your system you will find a ton of gunk that is corrosion related. From what I understand this is all because it is water based. Obviously we have all been using water based coolant for....ever. and have never had any corrosion related problems (given your not running tap water). Bit if your weird about little things like I am, its a piece of mind. Like I said, its an option, not a need. Thanks for clearing up the confusion though!

 

Hey guys,

Sorry about the delay in me posting a response. Turns out the thermostat was the problem. Thanks for all the suggestion! You guys rock.

 

*high fives!*