My 96 850 has been a very reliable car for myself and now has me worried due to a fault it has recently developed. It starts and runs fine and then steam starts to come from the expansion tank and the temperature passes half way on the gauge which I have never seen before. I was wondering if this is a common problem, it seems to hold pressure but allows coolant to flow throw the top of the tank. I have replaced the cap on the tank but problem still exists. If anyone has any ideas or knows how to fix the problem that would be greatly appreciated.
Thanks for taking the time to read this,
It could be as simple as the thermostat is bung which is common with these motors. Sometimes not easy to get the t/stat housing bolts undone , even for a mechanic i found out! But easy fix at home if yoy have tools and can get those bolts undone. Buy a T/Stat from a Volvo shop , repco charge 3 times the price of an independant shop...
At worst its a head gasket....
Look at the T/Stat to see if it is all twisted up and broken first.
BTW is it turbo or NA?
Is there any steam or water out he exhaust?
Any oil in the coolant ,, ie , milky looking.
When you pull the oil dipstick do you see fumes coming out? A way top check is a disposable gove on the dip tube with elastic band , if if blows the glove up.
Was the coolant changed recently? Could just be air in the system too so it needs "burping" properly.
Or did you change the coolant tank and then this happened.
Does it run OK?
yeah runs fine when not hot, oil and coolant not mixing, coolant was recently changed but done a couple of hundred kms since then. so I don't know what the problem could be.
Could just have air in system , they take a fair bit of time to get air out when refilled.
Have coolant bottle handy , warm up with reservoir cap off let it get hot and it will overflow and pump the air out if you rev it a little , when tstat opens ( put new one in) it will drop the level so add coolant and keep idling till the fans come on .
when you replaced the coolant did you put a 50/50 mix back into it?
Volvo runs the motors hot (ideal is 105C) so just water (of 5/95) wont cut it
Thermostat is a frequent failure as well