Radiator Coolant Help Please!!

WernerT4 · Post by **WernerT4** » 04 Dec 2008, 03:28

Hi I have an 98 S40 T4. What pre cautions should I take when I renew my coolant/water? Is there any way to get the air out of the system when throwing new coolant in? a Volvo mech told me that I shouldnt take that redish screw off to let the air go out because it always breaks.

Should I just fill it with the new coolant/water, start it with the coolant bottle cap off and wait for the thermostat to open and throw sum more in again? Please any advice will be much appreciated as I dont want to mesh up my first Volvo. Thank you.

Post by **billofdurham** » 04 Dec 2008, 12:55

Welcome to Matthew's Volvo Site.

When draining the water system have the heater control set to max hot. This allows the water to drain from the heater.

When refilling do it slowly, still with the heater set on max. From time to time massage the two big hoses to help expel air.

I am not a believer in leaving the cap off when the engine is running as I have seen cooling systems do a good impersonation of Old Faithful. Let the water circulate, with or without the cap, and again massage the two big hoses from time to time. Allow the system to cool and top up as necessary.

For once I agree with a Volvo tech - leave that red screw alone.

Bill.

WernerT4 · Post by **WernerT4** » 04 Dec 2008, 21:16

Thank u so much for the information Bill. I appreciate it very much. I recently bought this car and the other night when I took it out for a drive the right tank of the radiator (where the thermostat goes into) caught a crack for no reason. The car did not overheat or anything. Doesnt look like if its the head gasket..

I suspect it may be the thermostat or waterpump.. The temp always went to 88 degrees celcius and then the thermostat opened, drops to about 84 but then runs to 90 quite fast..sometime over 100 when left to idle for a while. The thermostat pipe also got very very very hot, it was untouchable.. What do u think what have may caused this problem Bill? Thanks again.

Post by **billofdurham** » 05 Dec 2008, 11:26

the right tank of the radiator (where the thermostat goes into) caught a crack for no reason.

Can you clarify the above? It may be that different terminology, caused by the big pond between the US and the UK, means different things but I read that as the radiator has developed a crack.

Bill.

WernerT4 · Post by **WernerT4** » 05 Dec 2008, 23:42

Thats correct yes. On monday night when I took her out for a drive to the store I saw a lot of coolant coming from under the car so I drove home and saw that the coolant is coming from radiator tank so I took the radiator out and saw a crack in the tank.There was no steam or so coming from the water bottle cap..The car's heat did go up to about 90degrees celcuis and then came back to about 84 and went back up again, tend to go up and down all the time..like if the thermostat is open and closing all the time.. Sometimes when on a mild day it will go up to 102 very very fast when standing still till the fan kicks in.

There is no oil in the coolant water, no milky stuff under the oil filler cap and on the dipstick. I didnt look for bubbles in the radiator bottle before I took the radiator out...so Im not sure. There is also NO smell of exhuast gasses in the coolant. Ive ordered a new radiator now and waiting for it to arrive. The radiator expert told me that its the thermostat.. What do u think? I dont think its a blown head gasket becuase there are no signs of it...or am I wrong? Please give me advice Bill I will appreciate it very much. Im very worried. Thank u.

WernerT4 · Post by **WernerT4** » 06 Dec 2008, 01:38

Oh yes and I forgot to mention, the thermostat pipe was so hot that it was actually impossible to touch and the other pipe at the other end of the radiator was not even mild..

Post by **MadeInJapan** » 06 Dec 2008, 07:47

I agree with the assessment that it is the thermostat...If you're changing it out, also change the temp. sensor at the same time. You're already taking that area apart anyway.