Fellow Bricksters,

I am going to replace the ECT sensor and thermostat which I bought from IPD on the weekend on my V70 T5. Currently the fan continues to run even after we have turned the motor off along with the check engine light coming on. I checked it with my OBD II reader and it refered to the coolant system. So for the price I have decided to do the change, not big $$$ so I decided to give it a shot.

Any thing that we need to be careful of when do the job?? Any advice appreciated
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1987 740 GL, 1987 740 HP Turbo, 1997 S70 T5 & 2001 V70 all still in the family.....

If the thermostat hasn't been replaced in a long time, do that at the same time.

To prevent coolant spilling, drain about 1 quart of coolant from the engine drain plug or carefully loosen the lower coolant hose from the engine side and drain 1 quart or so. Remember to replace the clamp and hose in the same position as they were in before and do not overtighten the clamp.

If you replace the thermostat, there are 2 stubborn T40 bolts holding down the cover. Buy a good quality T40 driver with a 4" extension to your ratchet. Press down very hard to "break" the bolt loose, the heads are easy to strip and if you do strip them it can be a nightmare. If one bolt head strips, I suggest tightening the other back down and having a mechanic help you out.

The ECT is quite simple to replace, but clean the plug before you plug it back into the ECT. A dab if di-electric grease is always helpful to keep any moisture out.

http://volvospeed.com/Repair/thermect.php

Klaus
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Volvoless. Sold the R. There is now a void...

Make sure you have a very good T40 driver, one of the screws is difficult to access and keep the driver straight. Loosen the rear most bolt first, that way if you get into trouble you can always get a new screw before continuing.

I flushed a quart of antifreeze from the bottom radiator hose rather than mess with the engine block drain. Just be careful to put the hose and clamp back in the same position it was before and not over tighten the clamp. Draining from the radiator drain won't help, and you do not want to spill coolant all over the alternator!!

Before you remove the thermostat, look at how it is placed. The dimple on top shows the difference from the back from front, and you want to insert the new one the same way.

Clean the connector to the ECT before re-installing. Di-electric grease is always welcome if you have some on hand, it keeps moisture out.

Klaus
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Volvoless. Sold the R. There is now a void...

Everyone,

Thank you very much. I will approach this job on the weekend with advice on given, Thanks again.....
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1987 740 GL, 1987 740 HP Turbo, 1997 S70 T5 & 2001 V70 all still in the family.....

I just recently finished this job and posted a warning about a problem I had while doing it. Basically, the bolts that hold the thermostat on can be seized enough that you could easily strip/round the torx head, necessitating some surgery to remove the bolt.

Here is the post:HERE
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1998 V70 AWD Turbo 180k+

I don't know about your particular car but many have their fans controlled by a sensor on the radiator which is different from the ECT sensor which is located on the cylinder head. I have had these fan sensors stick "on" on a couple of older cars. You can tell if the ECT sensor is ok or not because if the ECT sensor is bad the temperature gauge will read incorrectly vs the actual temperature of the engine and you may get a code as well. If the fan is on always, does the engine run too cool?

Thanks for the advice we replaced the ECT today and it has fixed all the dramas. Temp guage has come back to normal....
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1987 740 GL, 1987 740 HP Turbo, 1997 S70 T5 & 2001 V70 all still in the family.....