75 3.0 thermostat

[stustustu123]

Hello there,

The 75 seems to run a bit cool & I'm a little sus on the thermostat as it looks kinda old.  For peace of mind I'd like to replace it.  Having phoned around a few places I've been told these don't appear to be available any more & advised to fit a newer unit.  Has anyone done this and exactly what unit should I use?  One from a 24v engine or something else??

Any advice appreciated!

Cheers,
Stu.

[JOHN G]

Hi Stu

Before you change it what do you consider a little bit cool ?

From Alfa Owner:
"To help numerous owners on here to diagnose thermostat problems.
the thermostat is basically a mechanical valve that opens and closes in relationship to engine temperature,letting water to go to radiator to be cooled, so as to keep the engine running at near enough its optimum temperature usually around 80c to 90 c depends on diesel or petrol
a faulty thermostat will give cool running of engine therefore give the engine management system signals through temperature sensor, that the engine is still warming up so it will fuel accordingly.....using more fuel affecting drivability,and in winter heater not as good as it should be
remember this simple test is suitable for 99.9% of all engines that are water cooled


from cold start engine up and warm engine up
as engine warms up feel the top hose of the radiator(this hose is about 2" in diameter) and this should be cold (thermostat working)
if hose warms up with engine ,this means thermostat is passing and will need replacing
if your thermostat is working correctly after about ten minutes of warming up (depending on ambient temperature) hose should start getting warm as thermastat lets water through ,so just have a quick look to see what temperature gauge is at ,this should be around 80c or 90c depends on engine type"

John

[stustustu123]

I'm not sure how accurate the temp gauge is but in winter on the open road it will read between 60-70 deg.  As soon as I am sitting in traffic or in warmer weather it'll reach 80-90 which I'd consider normal.  Plus it uses a lot more fuel than I think it should so I suspect the lower temps are (as your description suggests) causing this.  Also the heater isn't THAT hot so it seems to all add up to a suspect thermostat.

[MD]

Good mechanical workshops have master guages for oil pressure and temperature (amongs other things) So you should be able to have the engine temperature tested before you do anything. Additionally, there are infra red themometers of the point and shoot kind that will allow the measurement of the engine temp. right at the thermostat housing to read the temp differential between the hot side and the cold side as it goes through its changes.

Just a thought.

[stustustu123]

Thanks for the advice.  So if it is bung, what do I do?  My question was really "what are people using if the original part is nla"??

Cheers,
Stu.

[MD]

If you have exhausted local suppliers, try overseas vendors, say in the UK. I cannot believe you can't buy a thermostat for a 2.5 litre engine. If I got that desperate, I would eventually just make one but I don't expect you are up that speed so keep shopping. You'll get there I am sure.

[Typhoon90]

Just use an aftermarket thermostat, Tridon will surely have something to suit, they make one for the 2.5 in my 90.

Regards, Andrew.

[scott.venables]

Andrew, what was the part number for the Tridon you used?  I fitted a Stant ST15-180 to my 2.5 which is what the catalogue reccommended and I had to machine a shallow counterbore in the top of the middle housing and cut the posts off the top housing.

Cheers, Scott

[Typhoon90]

Andrew, what was the part number for the Tridon you used?  I fitted a Stant ST15-180 to my 2.5 which is what the catalogue reccommended and I had to machine a shallow counterbore in the top of the middle housing and cut the posts off the top housing.

Cheers, Scott

Here's a great resource:
http://www.derek.com.au/tridoncooling.pdf
It would appear my car has some sort of aftermarket thermostat top housing, photos I've seen show the OEM thermostats as part of the top housing?

Regards, Andrew.