D5 Thermostat / water temp

[Garett]

Thanks for the input guys, the car is a 2001, the hose split because the fuel pump had been leaking diesel which caused the rubber hose underneath it to go soft and perish. I'm not entirely sure if they did a full coolant change and flush, I suspect they probably just replaced what had been lost.

[Garett]

Here are some pics from today of the temp sensor.

This is this morning after a 30 minute, 15 mile drive along at first country lanes and then 'A' roads, the ambient was between 0°c an 2°c.
The car was also left to idle on the driveway prior to the journey and defrost itself for 10 mins, which it did do and was frost free when I got in.



And this is the return journey along the same 'A' roads and then country lanes with an ambient temp of 8°c.

[hillbilly22]

A thermostat is designed to warm the engine to operating temperature quickly in any weather condition, it's main purpose is to then keep the engine at its operating temperature, usually 82 degrees, I have changed thermostats on a Laguna Dci and an Alfa jtd, both cars reached their temperature quickly and maintained it afterwards. I think after time they do not close properly, allowing water into rad and slowing down the warm up process.

[ianbr]

Pictures of temperature gauge look way too low. Mine has always been exactly in the middle and would take much less than 30 min to get there even if ambient were 0 to 2 degrees. Probably more like 10 min of running, possibly less

[Clan]

Originally Posted by Georgeandkira

Hello,
To Garett: How many miles and what year is your car? You split a hose so it must be reasonably old. Old enough for a thermostat to go bad I think.
To Clan: You never saw a stat go bad? England gets magic thermostats? That's great.
Mine went out in my 2002 petrol at ~123K with the same symptoms as the "big aluminum 5 cylinder engine".
I don't think the efficiency of any diesel engine translates into slower warm-ups compared to a petrol engine.
Every post I've ever read about this subject warns against anything other than OE thermostats. I bought a Mahler which is said to supply Volvo's stats.
Kira

yes i have seen volvo thermostats stick open over the last 3 decades , but only petrol ones after well over 100.000 miles and so far never had a D5 one stick open but this is obviously the case with Garrett . A D5 today took 1.5 miles to warm up from cold using 2500-3000 rpm on a short journey ...

[Chesterman]

In reply to the original question. I would consider the temp readings you have, (given the journey,) to be abnormally low. This is your warning that somthing is wrong. IMHO.

[Garett]

Thanks for confirming my suspicions chaps, bit of a pain as it went in for a service only a couple of weeks ago and they didn't pick up on it but then I suppose they wouldn't unless they took it for a road test from cold.

Does anyone know of a supplier of the thermostats other than the obvious Rufe or Parts For Volvos? They're around £100 on Euro Car Parts also. These are the full part with the housing but it was mentioned it is possible to just change the 'stat itself, where sells the 'stat alone? £100 seems a lot especially as you can get them from as little as £5 for some cars!

[outnumbered]

gates 7412-10514/ TH 35991 thermostat. i have one sat in the garage.
mike

[S60D5-185]

Originally Posted by Clan

yes i have seen volvo thermostats stick open over the last 3 decades , but only petrol ones after well over 100.000 miles and so far never had a D5 one stick open but this is obviously the case with Garrett . A D5 today took 1.5 miles to warm up from cold using 2500-3000 rpm on a short journey ...

That's about the same as my D5 185 S60

Darryl

[Garett]

I've now received one of the gates theromstats TH 35991 but its hasn't come with a rubber seal or any form of gasket, will this be ok?

Also I've whipped off the engine cover and had a look at where it lives. Is it just a case of undoing the 2 torx bolts to get access to the thermostat? One looks a bit of a bugger to get at as (I think) the power steering pump is in the way.