1999 S80 T6 Does it mean the head gasket need replacing?

[Riba]

Hello all, my first post here and a first Volvo for me. I like to dive under the hood with tools, and this forum is a great resource.

A short history (very short as most of it is unknown). Two days ago I bought a Volvo in the subject and I expected it will take some work which I was willing to accept. However car turned out to be cleaner than expected, runs very smooth, there are no weird noises coming out from anywhere. So far so good. The previous owner is not so skilled and said that something is wrong with the steering, turned out the steering fluid was low. Easy fix.

Engine itself is dry, no leaks anywhere. Oil is clean. After getting home from a 30 mile drive I heard gurgling after turning off the engine. I popped the hood and saw that the coolant is bubbling in the coolant reservoir. I read a lot about it in the forum and turned out it is not that uncommon. I did remove the cap after it cooled down a bit, but then decided to check it tomorrow during daylight.

True enough the coolant level was low (might have been right from the start, but a good part of it escaped when I removed the cap the evening before). I topped up the coolant and it has been fine for two days now, no bubbling or anything. However the engine temperature seems to be a bit higher than manual suggests it should be, and other owners confirmed it should be right in the middle. In my case it is like this:



It warms up in a couple of minutes and stays like this.

I was planning to replace the timing and serpentine belts along with the water pump and flush the coolant, but one owner told me that from his personal experience I am probably in for a engine head gasket replacement, and I have a uncomfortable feeling that he may be right considering I don't know the history of the car and it is past 100000 miles on odo. I'd like to hear second opinion, is there a way to confirm this without opening up the engine? The coolant is not oily or smelly so far. Any tips and suggestions are very welcome.

Thanks!

[kcodyjr]

If the head gasket was responsible for loss of coolant pressure, at least one of the following would be true:

* There would be white smoke coming out the tailpipe.
* There would be a visible oil slick on top of the coolant in the reservoir, and/or it would be cloudy.
* There would be coolant in the oil, making it thin and frothy.

You said some escaped when you opened it, so obviously there's at least some pressure.

If none of those is true, you probably just have a small leak that's keeping the pressure from getting all the way up to spec, allowing boiling. First suspect would be the cap. Then look where the hoses meet hardpoints. Also look carefully all around the radiator.

You might also have too much water in the coolant, allowing an unacceptably low boiling point. Use one of those squeeze bulb tester doodads to find out for sure.

[kcodyjr]

Also, the steady behavior at the gauge suggests there might be an out-of-spec thermostat in it.

I'm thinking that a blockage is unlikely, temperature stability would be more dependent on engine speed.

[Riba]

Thanks a lot, this sounds reassuring. Actually I had to top up the coolant with plain water at the time, but I already bought the antifreeze and will bleed the system and completely replace the coolant. It might be something as simple as that. I think the pressure is definitely there so you are right, it shouldn't point to a gasket...and I checked the coolant level, it seems to be stable. I will inspect the coolant line just in case.
Good point about the thermostat as well, I am going to check that too.
Regarding the three points above, I had point 4 happen to me on one of the previous cars. The gasket leaked in a way to let the coolant out where the belts and the covers were. I drove me crazy, took weeks to find. Oil was not milky, coolant was clear, no smoke and still it was disappearing somewhere and you could not see it. )

Not sure if this is possible on a Volvo engine, in this case it was an oldsmobile.

[difflock54]

I assume the radiator itself is in good condition ? If not that could make her run hotter.
Also check the overflow reservoir for any small split or the cap itself.
Often simply replacing the cap fixes these niggly little issues with coolant disappearing also.

if your temp gauge ever goes higher to the RED stop and switch off immediately.
Limping to the next service garage is not an option. Tow truck is cheaper than major engine overhaul.

[kcodyjr]

Actually, shutting it off cold isn't necessarily the right response. Even in normal conditions, the coolant keeps getting hotter after you shut it off due to the heat in the cylinder walls and pistons. It's just as likely that temperatures will reach damaging levels after it's shut off as while it's running.

I'd knock it into neutral, crank the heat, and hold it at 2K while I rolled it into the breakdown lane. If I couldn't get hot air, or if the coolant temperature didn't start dropping within a minute or so, then I'd shut off the engine and let the chips fall where they will.

[Riba]

Still no news as I am trying to find someone with a OBD scanner to get the codes before moving on. In the mean time I ordered one myself as I will probably use it regularly.
However I noticed something else that *might* be related to the original problem. The AC cooling is working, but heating is not working at all. I guess the first suspect is the heater core unit, but what might cause it not to give any heat at all? Maybe it is clogged? I should probably check if it is even there, I wouldn't be surprised if someone removed it altogether. What do more experienced say?

Thanks!

[kcodyjr]

Don't wait for the codes. Do the thermostat and ECT sensor. Go from there.

[Riba]

Thanks, I also found some good tips on one of the other threads regarding the heating problem:
https://www.matthewsvolvosite.com/forums ... php?t=6622

[Riba]

Haven't done the thermostat yet (I should get all the parts in about week or two), but I did get the EDB dongle and checked the error codes today.

Here is what I get:

P0030 - Powertrain
HO2S Heater Control Circuit (Bank 1 Sensor 1)

P0056 - Powertrain
HO2S Heater Control Circuit (Bank 2 Sensor 2)

P0156 - Powertrain
O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)

Where are these buggers and is there anything to try before buying new ones?