New 200 tdi Thermostat wont work.. twice !!!!

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landowner

landowner

Pensioner Pete
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Had two new thermostats (different makes) and neither will open. Engine hot and radiator, bottom hose and header tank stone cold.
Take thermostat out and all gets warm but not warm enough so water is circulating.
Tried another thermostat today and it doesnt open.
Supplier says they open on pressure so wont open in a cup of boiling water to check.
Any ideas please ?
 
Water pump ok because all is well without thermostat fitted. Runs cooler obviously but everything warm and some pressure at header tank.
l've just driven home about 4 miles and themostat not opened. Could be not up to temp so l'll go for a drive later and chech temps with laser gun.
 
Not opening in a cup of water is ****e. They work on heat not temp.

Tried 4 different stats till I found one that worked properly - and it wasn't genuine.

Genuine was off, bearmach1 was off bearmach 2 spot on and britpart was off.

Also does your system hold pressure? That made a big difference with mine
 
Boiling water in a cup is simply no good as the water cools down to quick once it hits the cup and the stat doesnt react instantly, what you need to do is using some garden wire suspend the stat in a kettle and watch the stat as the kettle boils.
Safety warning boiling water is er hot:D
Supplier saying pressure might have some relevance to new stuff but not on 200tdi engines.
Both my 200 stat doent open unitl they have done approx 5 miles, 3 miles of town work then 2 miles of 50 plus mph, my D3 is exactly the same.
 
My 90 heater is toasty after about 3 miles, I have half the rad covered and no fan.
Temp gauge goes to above normal after about 5 miles and when l stop l find an ice cold rad, bottom hose and header tank, engine feels very hot but not boiling and windscreen vent air burns your finger nails.
Could be that its not at 88 deg and thermostat ok ???
 
The thing is it can be difficult to tell with a 200, as an example few years ago I fitted new stat drove 12 miles to work, thought thats smells hot? ignored it and then after work drove home again thats running to hot, stat off and kettle tested new stat fubar! old one back in normal service resumed.
The cheap laser temp guns are actually quite good.
 
Drove mine 13miles other night and got excited with new turbo on so drove hard. Got to tesco and went to top the water up because it was only just above cold and I was worried it was low on water or some daft ****. Slowly opened cap no hiss like when hot and under pressure. Dangled my finger in water there but only warm plenty of it. Just a decent rad on it so 4 miles won't do much in this weather
 
I'll cane it for a few miles tomorrow and check it with my laser, checked it tonight when temp on normal and it showed 75 deg at the stat housing which is low even though heater nice and warm
 
flat said:
Well I have been having some weird over-cooling ( i have a mechanical gauge) - it would never get hotter than about 70c. I thought stat stuck open type issues so replaced it with a genuine waxstat one from a random online supplier. Engine now warmed up quicker but sat at 95c all the time which was a bit hot for me and gave no leeway for working hard imo. So i boiled my new (genuine) and old bearmach stats and got some surprising results

Bearmach old 88c stat - fully open at 83 in 8 minutes - dash temp gauge sits at 70c
Waxstat old 88c - fully open at 91c in 10mins - dash temp gauge sits at 92-95c

That surprised me, they are both way off. thought they perhaps were old stock or something so i brought a bearmach and a genuine again. This time i went for genuine direct from land rover (stratstones) and bearmach from paddocks. some more surprising results, this time i looked at which closed the quickest aswell.

Bearmach new 88c - stat full open at 87c in 10mins. Dash temp gauge 80c. Closed medium speed
Waxstat new 88c full open at 90c in 12mins. (not fitted to vehicle). closed very fast.

So i hedged my bets and fitted the new bearmach one. warms up nicely, temp gauge sits at 80c idling and 85c when driving so that makes me feel more comfortable.

Have kept the other 3 stats, as i have now a stat for super hot weather, and a stat for super cold weather. and a spare, that may or may not make my engine to hot.

The bearmach ones were £6 or so and the genuine £9.

anyway thats it, nothing else done :)

EDIT: If anyone is interested here is the lash up i made to pressure test the coolant system :D
Click to expand...

THis is what I found with 3 stats.

It could be that your stat isnopeninmg early preventing your engine getting up to proper temp.

Worth getting a pressure test to make sure your system is up to scratch
 
landowner said:
Had two new thermostats (different makes) and neither will open. Engine hot and radiator, bottom hose and header tank stone cold.
Take thermostat out and all gets warm but not warm enough so water is circulating.
Tried another thermostat today and it doesnt open.
Supplier says they open on pressure so wont open in a cup of boiling water to check.
Any ideas please ?
Click to expand...
they will open in a jug of water a cup probably has not enough volume of water and temp drops when a cold thermostat is dunked in, if it wont open in near boiling water its a poor part, very common nowadays
 
landowner said:
chech temps with laser gun.
Click to expand...

Do be careful with the laser thermos. FYI. Sorry if you already know this.

They can give differing results depending on the surface " finish / shine / colour" it is called emissivity. Plus make sure you are not too far away from the area being measured as they take a reading from a cone and the further away you are the more risk of outside influence/ missing your intended target.

I have taken extensive temperature measurements for work, on steel of differing surface finishes. In the end it was better to use a surface / contact probe to get a realistic measurement.

If you are going to check the temp of a given point of a given material and surface finish, then I would suggest using a surface probe to check your laser measurements if they are the same ( with in a tolerance ) then OK, if not then you will need to be aware of this.

Cheers
 
Well ....
Themostat opened today : )
Gauge went to normal and stayed there, unlike yeaterday and the day before when it went up towards the red.
Temp around the thermostat today was 80 ish deg, top of rad was 75, bottom of rad was 59 deg, bottom hose was 48 and the header tank was cold.
The only way l can get the header tank to get warm is to remove the thermostat and then the temps are cooler engine but warmer bottom hose and header tank.
l have rad blanked off 75% and no fan, temps are whilst town driving, in traffic mostly and towing a trailer..
 
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