View Full Version : Overheating on 850R

Sunday 1st May 2005, 20:21
Think the headgasket has gone on my 850R auto, the weather was very hot here today & i noticed that the engine cooling fan has been running constantly once upto operating temp. It stayed on for the whole journey,about an hour & the temp was just above the halfway mark. Near the end of the journey i had to put the heater on to bring the temp down as it was heading to the red. On the way back (another hour/40 miles) it was even worse, the temp gauge was constantly up at 3/4 & i was driving quite slow about 40 or 50 & not kicking down, everytime i went up a hill or kicked down the temp gauge started heading for the red again & i had to crank the heater on full blast to bring it down to just over halfway. Had to keep the heater on all the way home, also noticed that the car didn't feel as quick as it normally does, felt a bit gutless when temp was right up. It never went into the red but went right up to the edge before i put the heater on & this drew it back to just over half. Hasn't used any coolant, the expansion tank is still at the max. I'm sure its the H/gasket, any thoughts ? Are T5's prone to H/gasket failure, its done 133k with FVSH.

Thanks Simon.

Sunday 1st May 2005, 20:24
Its not uncommon for head gaskettes to fail, mine went at 170k, check the oil for cream and look for bubbles coming up through the expansion tank on tickover.

Monday 2nd May 2005, 10:21
Had a good check over it this morning, expansion tank still at max with no nasties in it, no sludge on oil cap or dipstick. Was hoping the thermostat might have jammed shut as the temp gauge seems to go up to engine operating temp a lot quicker than it used to from cold but i think it could be a blockage in the rad as the top hose is red hot & the bottom hose is cold after driving about 4 miles. Anymore thoughts please.


Monday 2nd May 2005, 10:59
Ma car overheated a while back and expansion tank was still full well after a refilled it after it spewed its guts all over the road :slap:

Changed the thermostat first and never got another problem since, hope its as easy for you but change easy and cheap bits first :wink:

Monday 2nd May 2005, 15:26
Removed the thermostat & boiled it up in a pan, it didn't open. Took the car for a good drive in traffic & on the motorway & it never got hot enough for the fan to come on. Sounds like the thermostats had it, will fit a new one in the week, meantime i'll just use it with no stat.


Monday 2nd May 2005, 15:41
Glad you found the problem!!! :)

Monday 2nd May 2005, 21:33
A bit off topic, but has anyone else noticed how many Volvo thermostats have failed CLOSED. In this day and age wouldnt you think they would fit fail open ones.I know mine failed closed a year or so ago so i made sure i replaced it with a guaranteed to fail open one, and it was cheaper than a genuine volvo one.

Wobbly Dave
Tuesday 3rd May 2005, 00:23
87 degree Tstat from my local motor parts shop costs 6 pounds!

Top tip for removing the tstat housing - undo the fuel line as it obstructs access to the back T30 bolt

Tuesday 3rd May 2005, 01:09
Could this not warp the head?I think tomorrow as well as 15 litres of oil and a filter,A thermostat is on the cards too. :eek: Missus is gonna love me spending another 50 on the car :slap: