new radiator on 740 GL

Tomca_ · Post by **Tomca_** » 15 Aug 2008, 06:22

Hello Everybody,

I have a 1990 Volvo740 GL, B200E. One week before, after 18 years, my original radiator went wrong (the side plastic part has broken), so I had to replace it.

Formerly, with the old radiator, the pointer of the temp gauge in the car stayed always in the middle, when the car warmed up. In this case the whole motor was hot (oil tank, air intake), you could hardly touch that.

However, nowadays, even in this hot summer, with the new radiator, the temp gauge rises up only to the third part of the scale. The motor is only pleasant warm, you can touch the whole motor (oil tank air intake), except the exhaust pipes (those are still very hot). Is this normal operation? Will be the same in winter? Or this is the normal operation and formerly was my motor too hot?

Tamas

Post by **billofdurham** » 15 Aug 2008, 12:16

18 years on the original radiator - not bad going.

I always like to see the needle sitting about the middle of the temp gauge. It is possible that your thermostat is stuck partially open not allowing the engine to warm up properly.

Bill.

Post by **sseir39** » 15 Aug 2008, 12:56

If your car overheated you most likely have a broken thermostat. The thermostat is designed to purposely break (one leg) in order to pass more coolant. Bet if you replace it your gauge will return to its previous setting. Also may want to do it before winter as the engine will take forever to heat up.

Tomca_ · Post by **Tomca_** » 17 Aug 2008, 05:28

Hello,

thank you for the advice, I think you have right, because the car was once overheated. I will replace the thermostat. I think I will have time to do it after two weeks (now I am going to holiday, without the car). I will tell you what I found.

Tamas

LaRy · Post by **LaRy** » 23 Aug 2008, 14:54

I think that you have a stocked broken thermostate, stocked in open position. Probably the old radiator was so dirty inside that the water flow through the radiator was reduced, for this reasion you got a warmer engine. Now with a new radiator with normal capacity, the cooling is to good with your thermostate stocked in open position.

Tomca_ · Post by **Tomca_** » 01 Sep 2008, 04:27

Hello Everybody,

you had right. Yesterday I replaced the thermostat and it was stocked open. Now the temperature is OK. Thank you.

And I can tell you another positive thing. Formerly I wrote in the forum about another problem: the RPM of the car was too small in idle, when the motor was cold. I could see that in summer but it was strong in winter: the car was shaking and almost stopping and I had to press gently the gas pedal to make the idle normal. Now, this problem also vanished.

Tamas

Post by **billofdurham** » 01 Sep 2008, 12:33

Thank you for the update.

It is good to know that you have cured more than one problem. The coolant temperature sensor would be sending false information to the ECU causing the idle problem.

Bill.