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1999 S80 T6 Overheating problem revisited

Everything on the Volvo S80. Sometimes called an "executive car", the S80 was Volvo's top-of-the-line passenger car. P2 platform.
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Riba
Posts: 66
Joined: 28 December 2013
Year and Model: S80 T6 1999
Location: Kuwait

1999 S80 T6 Overheating problem revisited

Post by Riba »

Some may remember this was discussed few months back, but I am back now with more data although I don't feel a whole lot smarter.

The problem:
- the car overheats mostly when A/C is turned on. It may be running hot even with A/C off but difficult to tell (see below). When running with A/C the coolant in the expansion bottle is boiling.
- the temperature gauge needle rises just a notch above the middle (normal?) position and never goes above it, even when the coolant is boiling as described above. Is this a broken sensor? I have seen similar reports elsewhere on the net but no definite solutions and the local mechanic said is it is "normal" which I'm not buying. One person said he had the exact same symptoms cause by a blown head gasket.

What has been done:
- replaced the thermostat. (did not help)
- replaced the water pump. Old one had crappy plastic fins, new one has metal ones. (did not help)
- replaced the expansion bottle. (this helped but mostly by preventing the coolant to leak out after pressure builds once the car is stopped)

At this point I am suspecting three possible solutions, ranked by how painful they are :):
1. At the moment I am using the regular Prestone coolant. I am aware that I should be using HOAT coolant, but that thing is not readily available here. I can get the original stuff from the dealer but I am wondering if it is even remotely possible this will make a difference based on the problem description? It is probably worth a shot.
2. Clogged radiator. I can feel a coolant flow on the top hose, but when feeling the bottom hose it it also very hot to touch. It may point to the flow problem, most likely in the radiator. When doing the coolant change (see above) I will flush the radiator. Is it possible to diagnose a problem with the radiator at home or does it need to be done by a shop?
3. Lastly, might be a blown head gasket. Oil is fine, and I can't see a change in the coolant but of course it is hard to say without the leak test which is not available here. I will pull the plugs these days and check if there are signs of burned coolant. There is some white smoke coming out of the exhaust but only after starting cold, and the mechanic said it is a evaporation in the turbo. It goes away when it warms up so it probably isn't the coolant getting into the combustion chamber, or am I wrong?

I am at the point to give up on completely fixing this car and use it for my short commute to work, and get something else to drive my family around. :)

Also, keep in mind that this is going on in harsh Kuwait climate (temperatures are sometimes reaching 50+ degrees Celsius)

Comments and ideas are appreciated!

majorcode
Posts: 55
Joined: 11 June 2012
Year and Model: 1999
Location: Riyadh

Post by majorcode »

Hi Riba,

Volvos are highly engineered cars, therefore it is better to fix all the problems rather suspecting or fixing one problem.

As per your given information I suggest go for Engine pressure test and then radiator.

but so far I am 75% sure your head gasket is blown partially.

Regarding coolant I always use Volvo genuine coolant but in your case I suggest fix basic problems before top up Volvo coolant.

precopster
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Post by precopster »

Don't rely on guesswork.

Did you replace the housing of the thermostat which contains the all important coolant temp sensor ?? If it's out of calibration it can easily make the engine coolant boil.

Speaking of which are you using a 50% ethylene glycol mix ?

After replacing the coolant temp sensor monitor the coolant temp with a scanner and be certain the fan is coming on at the correct temperature of around 98degC
Current cars VW Transporter 2.5TDI, 2010 XC90 D5 R Design

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regent
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Post by regent »

If I may add, the rad fan should also run whenever the AC is engaged, regardless of the EC Temp.
Example of Precision: Measure with a Micrometer, mark it with Chalk, and then cut it with an Axe.
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Riba
Posts: 66
Joined: 28 December 2013
Year and Model: S80 T6 1999
Location: Kuwait

Post by Riba »

majorcode wrote:Volvos are highly engineered cars, therefore it is better to fix all the problems rather suspecting or fixing one problem.
Sometimes I would go as far as to say they are overengineered. :)
majorcode wrote:As per your given information I suggest go for Engine pressure test and then radiator.
but so far I am 75% sure your head gasket is blown partially.
I agree with you. Wanted to check if there is anything else I can do before taking it to pros. I am not sure it would be worth rebuilding the engine, but a friend did a head gasket job on a Nissan at a shop nearby and the total was around $700. As I already invested a bit to get the car in a decent shape it might be worth a shot.
precopster wrote:Did you replace the housing of the thermostat which contains the all important coolant temp sensor ?? If it's out of calibration it can easily make the engine coolant boil.
I did not, it seemed to be ok. Visually the sensor looked fine, but I guess there are clear signs that it is not really working as it should. I'll get a new one just to get a proper reading and see what will happen.
regent wrote:If I may add, the rad fan should also run whenever the AC is engaged, regardless of the EC Temp.
Forgot to mention that the fan turns on, and kicks into high speed with A/C on, just as it should.

Thanks everyone.

majorcode
Posts: 55
Joined: 11 June 2012
Year and Model: 1999
Location: Riyadh

Post by majorcode »

Riba!!! in case you plan not to continue with this s80, let me know, I might need parts :)

Cheers! and good luck for sure.

Riba
Posts: 66
Joined: 28 December 2013
Year and Model: S80 T6 1999
Location: Kuwait

Post by Riba »

majorcode wrote:Riba!!! in case you plan not to continue with this s80, let me know, I might need parts :)

Cheers! and good luck for sure.
Haha, sure! As I need to get a second car for my wife anyway, I am considering using the Volvo as my 15 minute daily commute to work as it is until it burns out. There are brand new engine mounts, water pump and belts inside.

majorcode
Posts: 55
Joined: 11 June 2012
Year and Model: 1999
Location: Riyadh

Post by majorcode »

frankly speaking this model made me automotive geek, though i never been and now I feel the more problems my s80 gives the more I learn and feel more confident to own Euro cars, as my next will be Audi.

Sounds good about the items you placed in. Keep posting the s80 challenges ;)

Riba
Posts: 66
Joined: 28 December 2013
Year and Model: S80 T6 1999
Location: Kuwait

Post by Riba »

I learned a lot too, I wish I had a suitable place to take the thing apart myself. :) Before going that route I need a backup vehicle anyway.

Back home I have a '86 Audi, was my daily ride since I bought it in 1996, and never had a single problem. Very easy to work on as well unlike some other...ahem...brands. :)

precopster
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Post by precopster »

Audis (& VWs) have changed since '86. Today's layouts will have the home mechanic's head spinning.

We owned a '79 Audi 5E in the 90s (5 cylinder North/South configuration with FWD) and we loved it. Very easy to work on and looking back on it don't know why I sold it. It was on its 2nd $300 fuel pump in under 2 years and at the time there were no online options. Big car that handled on rails.......

Give that sensor a change. Early on in my Volvo career I replaced an engine because of a coolant sensor. :oops:
Current cars VW Transporter 2.5TDI, 2010 XC90 D5 R Design

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