Inline Thermostat

[clf]

Originally Posted by kelvo

Not Rover or a diesel but I had a similar problem with my Volvo 740. Around town it was quite happy with the gauge at normal but on faster driving I tended to notice the temp gauge drop right down, but not always. Simple enough job to whip the elbow off and take the thermostat out and put in a saucepan of water, from what I discovered it was sticking open very slightly. Obviously around town it was able to warm up but on the motorway, the increased air flow cooled it down too much. New thermostat and was good as gold - thermonuclear heater restored.

Years ago with diesels you could probably blank off most of the radiator in cold weather and not cause any problems.

I have experimented with blocking upper and lower grills. Covering the grills completely with tape, total blocking. It didnt work lol. It allowed the car to heat up a little quicker (5 miles instead of 7 - 5 is normal now with a decent inline fitted), but because the thermostat opened early (the common failure issue of our diesels). The hottest over a 20 mile drive including motorway speeds, was 92, settling down to 80/82 instead of the previous 75/78 when not under load.

Blocking off the grills does reduce power slightly, as the intercooler will not be blocked too. To be honest, I didnt notice a great loss in power, but I wasnt monitoring it.

I did have this issue with an old Carina years ago, dropping a sheet of cardboard between the grill and radiator emulated it having a thermostat, which it turned out it didnt have lol.

[clf]

Originally Posted by Daveluck

But Mike, I thought the issue is that original thermostats themselves fail? Ie they stay open therefore continually cooling the engine?

I thought the inline simply replaces the work of the non functioning OEM thermostat. In other words the engine will produce and retain enough heat if you have a functioning thermostat.

My inline definitely works. I have more heat but it is still too low. Sits at 83c which I think is probably about 10c too low but that is considerably better than the 65c it was sitting at.

82 is an acceptable value for most, when the original opens at 88. I wanted a higher figure also, so fitted a Wahler one 3 or 4 years ago. Still showing as opening at 88 degrees. Wahler produce a 92 version, but it is difficult or expensive. The 89 degree one is around 15 quid, and quite beautiful compared to others.

One other important thing to check prior to fitting, is to make sure the cup doesnt leak much. Some have a small pin hole, with nothing more than a drip when testing.

quick leaking bowl video

Wahler non leaking video

[Daveluck]

Originally Posted by Mike Noc

Once you have done a few it isn't much of a job.

I'll take your ( very experienced ) word for it.

I've been deliberately avoiding moving the the original stat. If there's a pipe to be bent, an o ring to nip and a 3 year guaranteed OEM replacement to fail after 6 months then I'm your man. So I've taken the path of least resistance and fitted the in line.

I did search a couple years back but no one on here could recommend a decent unit. I know there was talk of DMGRS MK2 housing. But the jury was still out.

At some point I suppose the o ring will fail or the case will crack and I'll have to do it.

Hopefully by then there will be a decent thermostats and housings.

[Daveluck]

Originally Posted by clf

82 is an acceptable value for most, when the original opens at 88. I wanted a higher figure also, so fitted a Wahler one 3 or 4 years ago. Still showing as opening at 88 degrees. Wahler produce a 92 version, but it is difficult or expensive. The 89 degree one is around 15 quid, and quite beautiful compared to others.

One other important thing to check prior to fitting, is to make sure the cup doesnt leak much. Some have a small pin hole, with nothing more than a drip when testing.

quick leaking bowl video

Wahler non leaking video

Yes i have the wahler...Infact I'm fairly certain I got it based on one of your posts.

I.d love to get my hands on the 92 but as you say either not available or so pricey you could buy another 75!