V70R coolant headache.

obayha · Post by **obayha** » 25 Jul 2013, 14:07

Agree with the pressure test to make sure it is holding pressure. The $31 spent on Stant was well worth it for me. I never over heated, just lost coolant.

Jockjunior · Post by **Jockjunior** » 26 Jul 2013, 11:59

Hi it's a 98' V70R AWD Auto, it's not bubbled over since seems to be kind of okay it's holding around the half way on the temp gauge, i have done 2 runs in car since and at one point it rose to just below the red for 30secs before returning to half, there is a very very slight weep at the bottom corner of the rad!

I did however tighten the cap really tight although this is only a few months old, I think I'll still get it tested then get a new rad and another cap for good measure?? Can sensors make this kind of thing happen?

Post by **mikealder** » 26 Jul 2013, 14:23

A faulty sender unit, a thermostat that sticks shut or a loss of pressure can all lead to the temp gauge going high but the coolant boiling out and escaping from the expansion tank only point at a stuck thermostat or loss of pressure in the cooling system, this is assuming the radiator cooling fan is correctly operating at the desired temperatures - Mike

Jockjunior · Post by **Jockjunior** » 03 Sep 2013, 15:46

I have no sign of the head going at all but the coolant still is bubbling over, I have just had the coolant temp sensor coming up as a fault, can this cause these issues?

Post by **erikv11** » 04 Sep 2013, 00:14

What Mike said: A bad sensor can cause the gauge to spike when the coolant isn't actually hot, but it won't cause the coolant to boil. No, the temp sensor is not the problem.

Best-case possibilities:
(1) Faulty thermostat. Run it for a week without the thermostat, or get a new one. This is cheap and easy to try you really must do it.
(2) Cooling fan not coming on when it is supposed to. On this site there are instructions for testing the fan and relays.
(3) A leak somewhere, that mended radiator is a very good candidate for a leak. Several people have mentioned the solution: do or get a pressure test.

I would test those three things, one at a time, and report back the results as I got 'em.

Post by **jblackburn** » 04 Sep 2013, 08:48

erikv11 wrote:What Mike said: A bad sensor can cause the gauge to spike when the coolant isn't actually hot, but it won't cause the coolant to boil. No, the temp sensor is not the problem.

Ah, but it would IF the cooling fan is not coming on when it should!

Post by **erikv11** » 04 Sep 2013, 08:57

Oh, yes good call!

Jockjunior · Post by **Jockjunior** » 13 Sep 2013, 15:28

Just did a block test again and it turned yellow, so that'll be that then!

Post by **rspi** » 14 Sep 2013, 05:46

The coolant coming out of the coolant resivoir is a sign of a bad head gasket.

Also, if you overheat the car/motor, it will likely damage the coolant temp sensor.
Read the info on this link:

http://atthetipwebs.com/technologyinstr ... gasket.htm

Post by **rspi** » 14 Sep 2013, 05:51

Oh, as for what Mike said about coolant boil & fan coming on..

Coolant under pressure boils at 275° F, the thermostat in these cars is suppose to be fully open at about 193° F. The fan will come on at 216° F and will go back off at 205° F.

V70R coolant headache.

Re: V70R coolant headache.