1.9TD Pressure in coolant (?not headgasket?)

[Bobafett]

Hi all,

New to this forum and looking for some advice on a weird issue I have..

Bought a 2000 V40 1.9 diesel a couple of weeks ago and noticed over the past week that there was loads of pressure in the coolant even when cold (top hose rock hard) pulled the expansion tank cap of, started the engine and could see air bubbles coming from the radiator overflow pipe in the tank.. I flushed and bled the system thoroughly but no improvement. I was pretty sure it must be exhaust in the coolant so did a chemical test today but the fluid stayed blue! Checked on the exhaust to make sure kit was ok and sure enough it turned yellow there?!?

Car runs great, starts on the button and there is no mixing of oil in water or vice versa..
Any ideas where this air in the cooling system is coming from? I am stumped!!

[corbsxc90]

Cooling systems are supposed to pressurise to raise the boiling point of the coolant, If you have too much pressure and no signs of exhaust gases, my first thing would be to replace the header tank cap as the valve may have stuck. It should bleed pressure off above approx 16-18psi and then when system cools and contracts should allow air back into the system.
Try this first as it a fairly cheap thing to try and quite common.
Regards,
Chris

[m1tch1987]

The overflow tank will gradually take coolent and also replace it depending on how hot the engine is as its all pressurised - its why there is a min and max mark on them so that the engine doesn't fill up the tank completly or indeed suck in air.

Are the temperatures stable?

[Bobafett]

Thanks for the replies, I will order a new cap but seems odd that there are air bubbles visible from the overflow in the expansion tank??

Temperature is fine, never overheats but does take a while to get to the middle of the gauge from cold (about 15 -20 mins)

[gatos]

It should warm up in 2-3 minutes, or a mile or two. It would be a good idea to replace the thermostat

[Biotoxic]

Make sure that the thermostat has been replaced properly.

http://volvoforums.org.uk/showpost.p...14&postcount=3

[Bobafett]

Ok, cheers guys, will replace the thermostat this weekend and see how it goes...

[corbsxc90]

How did it go?

[Biotoxic]

I have noticed one thing, If it is a new member and he has found a solution it means that the problem was fixed, in this case thermostat was at fault/assembled incorrectly

[skyship007]

This is a link to Vadis doc on how to install the thermostat for the 115hp 1.9
diesel:
http://ww2.justanswer.com/uploads/en...nformation.pdf
Was the vent hole wrong or something??

Originally Posted by Bobafett

Ok, cheers guys, will replace the thermostat this weekend and see how it goes...