in line thermostat

[david2000]

hi to all
today I fitted a in line thermostat to my 75 diesel,started the engine and bleed the system,run the engine temp went up to 96 c and the cooling fan came on then I tried the heater and it was hot the switched the heater off and let the engine come up to temp until the fan came on,then I took the car for a spin down the road temp was between 76 c to 83 c tried the heater it was hot got back home parked the car ran the engine temp was 83 c turned the heater on to 28 c it was hot but the cooling fan came on and I don't know why can anyone tell me why this is
all the best david

[another_clean_sheet]

David, The first thing I would do seeing you have taken the car for a spin is to rebleed the system. I needed to do this after I fitted an online thermostat as I had an airlock in the cooling system.
Mike

[Mickyboy]

Ideally the temp should get to 88 degrees, I have a inline that I fitted and found that I suffered no airlock, what fan have you got 2 or 3 speed ?

Regards mick

[DMGRS]

It sounds like there was an airlock at first, that has now sorted itself out.
The diesels are very cool running - an 86 degree thermostat will tend to sit in the low 80s, and an 88/89 item in the mid 80s.
They're very hard to keep hot!

[Union Wheels]

You can get the diesel to run 95C and back to 85C cycling continually if you fit an alloy housing in the top hose and a 92C stat.

Pete.

[david2000]

hi to all
the fan is a 3 speed and I bled the system when cold and after a test run,on auto the fan comes on but change it to hi the fan go,s off in econ the fan does not come on and in hi mode in econ,in defrost the fan comes on, I have owned the car for 3 years and this is the hottest it has been,the temp gauge never went above half way
all the best david

[T-Cut]

- - - this is the hottest it has been,the temp gauge never went above half way

Nor should it. The 'normal' is up to 115C, which is rather warm for any engine.

I thought you were running in diagnostic mode?

TC

[SD1too]

... on auto the fan comes on but change it to hi the fan go,s off in econ the fan does not come on and in hi mode in econ,in defrost the fan comes on ..
What you are describing there David is the fan's response to the air conditioning and it is working correctly. It will only respond to engine coolant temperature when this reaches 100°, and you'll have to have the air con. off to hear it starting.
... the temp gauge never went above half way ...
The gauge will remain at "half way" even if your engine seriously overheats (temperatures up to 115°). You have to use the instrument pack diagnostics to find out what the actual temperature is.

Simon

[david2000]

hi to all
yes the fan run continuously for more than 2 minute on demist
today I checked the water level and toped up then I started the car and bled the system no air came out I then connected the t4 and went to the engine overview from cold these were the readings
11.27 water temp cold 6.85 c
11.35 water temp 53.55 c
11.40 water temp 73.55 c
11.45 water temp 79.35 c
11.50 water temp 82.35 c in line thermostat opens
11.55 water temp 87.95 c
12.00 water temp 93.35 c
12.03 water temp 99.16 c fan comes on
while doing this test I tried the atc on auto and the fan did not come on
also the heater was hot

[SD1too]

yes the fan run continuously for more than 2 minute on demist
That's fine. In 'demist' mode, the air conditioning will operate with the fan running in slow speed continuously.
11.50 water temp 82.35 c in line thermostat opens
11.55 water temp 87.95 c
12.00 water temp 93.35 c
12.03 water temp 99.16 c fan comes on
I have no experience of the diesel engine David, but from what I've learned on the forum your engine appears to be overheating. Have you inserted the in-line thermostat the correct way around?
while doing this test I tried the atc on auto and the fan did not come on ..
That sometimes happens in 'Auto' mode. It's why we always recommend using 'demist'.

Simon

[david2000]

yes the way that was shown on this forum

[bl52krz]

The information for the temperature of the diesel thermostat is:-opens at 88 degree's. No information on when it is fully open. So the fact you are seeing much higher temp suggests that something is amiss.

[DMGRS]

hi to all
yes the fan run continuously for more than 2 minute on demist
today I checked the water level and toped up then I started the car and bled the system no air came out I then connected the t4 and went to the engine overview from cold these were the readings
11.27 water temp cold 6.85 c
11.35 water temp 53.55 c
11.40 water temp 73.55 c
11.45 water temp 79.35 c
11.50 water temp 82.35 c in line thermostat opens
11.55 water temp 87.95 c
12.00 water temp 93.35 c
12.03 water temp 99.16 c fan comes on
while doing this test I tried the atc on auto and the fan did not come on
also the heater was hot

That's normal - as the car isn't moving, so there's no air flowing through the radiator to cool things down. The car will keep getting hotter until the fan kicks in.

[SD1too]

That's normal - as the car isn't moving ..
It depends whether the engine was already at normal operating temperature or started from cold. If the latter, the engine isn't under load and doesn't produce enough heat to reach the fan triggering point. At least that's how my petrol engine behaves.

So David, did you start the engine from cold when taking these temperatures? Edit: Sorry David, Mat has pointed out that you have indicated that you did start the engine from cold.

Simon

[DMGRS]

It depends whether the engine was already at normal operating temperature or started from cold. If the latter, the engine isn't under load and doesn't produce enough heat to reach the fan triggering point. At least that's how my petrol engine behaves.

So David, did you start the engine from cold when taking these temperatures?

Simon

Taken from his post:
11.27 water temp cold 6.85 c

My diesel will reach fan temperature if left running on the drive - I did this test as part of the V3 thermostat testing.

[SD1too]

Taken from his post ...
Thanks Mat. :duh:
My diesel will reach fan temperature if left running on the drive ...
After being started from cold? What's the temperature of your thermostat?

Simon

[DMGRS]

Thanks Mat. :duh:

After being started from cold? What's the temperature of your thermostat?

Simon

It is indeed from cold, but granted it takes a while - around 45 minutes. It's on the OEM thermostat now, rated to 88 degrees from memory. :)

[SD1too]

... but granted it takes a while - around 45 minutes.
:bigsmile:
Mat, with a punchline like that, you should be on the stage. :clap:
Simon

[david2000]

hi to all
if you look at the readings I posted the fan comes in at 99.16 c and the car was parked while taking the reading
this morning I took the car for a test drive and after 4 miles the temp gauge went up to 1/4 stopped for 30 minutes (went shopping) started the car drove another 2 miles and the temp gauge went up to 1/2 way and on auto the heater was hot
all the best david