D5 Thermostat / water temp

[Garett]

I'm not sure but I think the thermostat on my D5 might need changing.

It takes around 10 minutes for the needle to get to 1/8th and around 20+ mins to get to near its normal operating temp which is around half, or just a little bit under halfway on the temp display.

This is even when I'm straight onto the motorway within 5 mins of starting from cold and its at a steady 2k rpm.

Is this normal?

[Bill_56]

My 2.4D always took a good 10 miles or more, and perhaps about 10-20 minutes, to reach normal temperature. Various diesel courtesy cars I've had from Volvo over the years were the same, I think its normal.

The salesman who sold me the car explained that, owing to the long warm-up time, electrically heated seats are more than a novelty on a modern diesel - I used them every journey (in winter). I think it's just the price you pay for diesels being more efficient. More of the fuel's energy is turned into kinetic energy for the vehicle, and less wasted as heat.

[Brendan W]

Mine is generally up to operating temp after 6 -7 miles from cold on open roads.
Last winter there was one day that it stayed below normal after 30 mins of crawling in town. Ambient was -5C. Is this a change from normal or are you new to the car?

[Garett]

The coolant was changed about 2 months ago after a hose split, after this it seemed to take longer to warm up but maybe its because the cooling system wasn't working effectively before because of old coolant. I think its just more noticeable now the weather is getting colder.

I suppose diesel burns cooler and also with it being a big 5 cylinder engine takes longer to heat up and get the blowers warm.
I'll agree with the heated seats statement too, on the highest setting which seemed way too hot in all other weathers, this will be the first winter with this car so I've not used it in properly cold weather yet.

[Brendan W]

Don't think a coolant change can double warm up times. Which hose split and what was done at the coolant change ? Did they flush ?

[Clan]

Originally Posted by Garett

I'm not sure but I think the thermostat on my D5 might need changing.

It takes around 10 minutes for the needle to get to 1/8th and around 20+ mins to get to near its normal operating temp which is around half, or just a little bit under halfway on the temp display.This is even when I'm straight onto the motorway within 5 mins of starting from cold and its at a steady 2k rpm.

Is this normal?

What you said above in red is the key , it should reach exactly halfway and stay there when warm and never drop . perhaps the thermostat is faulty , it will be the first i have come across in 10 years since the D5 came out though if it is faulty ... about £100 ...

[outnumbered]

you can change just the the stat itself for just under £30 without going to the dealers for the complete sheebang.
mike

[Gazdok]

Mine failed on a D5 about 2 years ago in the winter. The needle never reached the centre.
I changed it - a bit of a pain, but o.k. with the right tools - and the needle was dead in the centre again.

You might get it cheaper through Simon (Rufe). I was looking for the thermostat only and could just find the complete housing for a D5. The thermostat alone was available for a T5 but it is a different size.

[outnumbered]

gates 7412-10514/ TH 35991 thermostat.
mike

[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