V70 Thermostat question

[Tony Rama]

Hi,

I have a 1999 V70 B5254 T. Discovered the previous owner has taken out the thermostat.

It should be 90 degrees according to the chassis no.

My local parts dealer sold me a BGA CT5484 supposedly for my model, but it has an opening temp. of 92 degrees.

Will it be OK to use this or will running at 92 adversely increase the pressure in the system, or upset the ECU.

Any advise would be much appreciated.

Tony

[Dippydog]

Assuming this is a petrol engine Haynes list two types of thermostat.Type 1 opens 87 C and is fully open at 102 C.Type 2 opens at 90 C and is fully open at 105 C.What the difference is between the two types[other than temperature ratings]I don't know.For peace of mind personally I'd source a proper 90 C one,although I don't really see any harm in fitting the one you have-others with more knowledge than I will probably be along soon to advise better?

[Tony Rama]

Sorry. Yes. It is petrol.

Any other opinions on 90 degree verses 92 degree thermostats?

[Clan]

Originally Posted by Tony Rama

Sorry. Yes. It is petrol.

Any other opinions on 90 degree verses 92 degree thermostats?

I always fitted 92 degree thermostats to older volvos , It helps with the efficiency and makes a noticeable difference to the heater . The radiators have such a big reserve built in that there were no problems in the summer . Go for it ..

[canis]

I personally think 2° will not make the slightest bit of difference. Although the thermostat has a rating, there's almost certainly variance between one part and another. And in any case, the engine has considerable differences of actual temperature all over the place.

More important is consistency. Put the thermostat in and forget about it. Yes, there must be some effect, in theory. In reality, there are too many other variables, it pales into insignificance. One would not sensibly argue, for example, running the cabin heater at full heat would affect engine temperature. Yet necessarily it must be taking it's heat, therefore the coolant necessarily must be cooled at least a bit. Should we worry? Of course not. It's all about perspective.

[Clan]

Originally Posted by canis

I personally think 2° will not make the slightest bit of difference. Although the thermostat has a rating, there's almost certainly variance between one part and another. And in any case, the engine has considerable differences of actual temperature all over the place.

More important is consistency. Put the thermostat in and forget about it. Yes, there must be some effect, in theory. In reality, there are too many other variables, it pales into insignificance. One would not sensibly argue, for example, running the cabin heater at full heat would affect engine temperature. Yet necessarily it must be taking it's heat, therefore the coolant necessarily must be cooled at least a bit. Should we worry? Of course not. It's all about perspective.

It makes a noticable difference I said above , That is down to practical experience over hundreds of cars and 30 years ! The gauge will read about a needle width higher in 240's . And if you are used to Volvos you will know the temperature gauge is rock stable , same position whether it is a 30 C hot summer or -10C cold winter .

[canis]

Originally Posted by Clan

It makes a noticable difference I said above , That is down to practical experience over hundreds of cars and 30 years ! The gauge will read about a needle width higher in 240's . And if you are used to Volvos you will know the temperature gauge is rock stable , same position whether it is a 30 C hot summer or -10C cold winter .

Yes, our gauge is rock stable too. Winter, Summer, come rain or shine, it always levels off to the same point. That's what I meant by consistency. Noticing the needle difference is testament to the sensitivity of the sensor and gauge, also good things. What I was trying to say, is 2° either way is not harmful to an engine and will not affect it's performance or longevity in comparison to other more vital considerations.

[Tony Rama]

OK. Wacked in the 92 degrees one. Immediate results.

Engine reaches operating temp. (needle horizontal) in about 2 miles. Before, without a thermostat is wasn't reaching OT in 25 miles or half an hour. In this weather the temp. gauge needle was constantly sitting at about a 1/4 on the motorway. It would eventually reach OT with town driving.

Previously I was getting 20 mpg (its an auto). It's doing better than that now, but not sure how much yet.

Am I right in thinking the auto gearbox cooler is incorporated in the water rad? If so it will help to bring the auto oil temp up to OT quicker.

Anyway, the engine feels a bit more lively and smoother now it got a thermostat!

Thanks to everyone for your advise.

Tony