156 jtd running very cool

[dirtyjohn]

im not complaining too much about this but i wonder if anyone has a similar experience.

my 156 jtd 2.4 runs very cool(below 1/4) mostly.i have let it idle and when it hits just over 90 degrees the fan does kick in and it comes down.obviously in heavier traffic its a little warmer but as soon as i get her going again the temp comes down immediately.

[Pud237]

Your thermostat is stuck open. You need a new one. Common problem, I had the same on my 2.4 JTD.

Should get up to about 85ish and stay there. If it gets hotter than 90ish the fan will come on and cool it down.

[longprest]

Just changed the thermostat on my 2.4 Jtd was running at 72ish now upto 90.........what a pig of a job and I used to be a mechanic! Tried to cut corner and not completely remove Egr cooler - bad idea, if you loosen thermostat and Egr off you can slide Egr in and out makes it a lot easier, time taked nearly three hours, reckon I could do it in under two if I ever had to do it again (hopefully not)
Why are these so prone to failure? never had a problem with Stilo Jtd and its almost same set up

[156Chris]

Originally Posted by longprest

Just changed the thermostat on my 2.4 Jtd was running at 72ish now upto 90.........what a pig of a job and I used to be a mechanic! Tried to cut corner and not completely remove Egr cooler - bad idea, if you loosen thermostat and Egr off you can slide Egr in and out makes it a lot easier, time taked nearly three hours, reckon I could do it in under two if I ever had to do it again (hopefully not)
Why are these so prone to failure? never had a problem with Stilo Jtd and its almost same set up

Better than me!!! took me 4 hours!!! (yet again think I could do it in 2hours were I ever to do it again ...)

[Pud237]

When Jus at BMC did mine for me it took him not far off two hours. And he's been working on Alfas non-stop for 15 years..

Pig of a job.

[Starsky]

Great! I get my new stat tomorrow. I'm not looking forward to this job

[dirtyjohn]

ah crap.so i dont suppose anyone can tell me where and how to do this job?

[Buzz84]

funnily enought i noticed that my car was always sitting around 70 on the dial, so took it on a longer run and it stayed there. so came to the conclusion my thermostat might need replacing. this has just confirmed it.

although i have noticed that the cooling fan kicks in as the needle goes over 70 and turns off as when it drops below which is peculiar as its supposed to be at 90 (from what i have read).

where's the best place (ie Cheapest!!!) to get one?

[Mark_JTD]

Try giving Steve a bell at Alternative Autos on 01484 865086 but have your VIN/chassis number handy as he'll need it to order the correct part.

Cheers,

Mark

[johnnygal]

Originally Posted by Buzz84

funnily enought i noticed that my car was always sitting around 70 on the dial, so took it on a longer run and it stayed there. so came to the conclusion my thermostat might need replacing. this has just confirmed it.

although i have noticed that the cooling fan kicks in as the needle goes over 70 and turns off as when it drops below which is peculiar as its supposed to be at 90 (from what i have read).

This could well be a faulty dial reading and not the thermostat, as is the case for me. Mine sits at about 70 (on the dial) with the same symptons as yours but I confirmed with plugging in an EOBD reader that the coolant temperature is in fact ok, at about 85.

[156Chris]

Originally Posted by Mark_JTD

Try giving Steve a bell at Alternative Autos on 01484 865086 but have your VIN/chassis number handy as he'll need it to order the correct part.

Cheers,

Mark

+1 that's where I got mine from, best price I found and was delivered the next day

[Starsky]

Originally Posted by johnnygal

This could well be a faulty dial reading and not the thermostat, as is the case for me. Mine sits at about 70 (on the dial) with the same symptons as yours but I confirmed with plugging in an EOBD reader that the coolant temperature is in fact ok, at about 85.

Does that mean that your temp sender isn't working then or is it the actual dial that's duff?

I went to the stealer today and was quoted £84+Vat for the stat

This includes the housing and a new temp sender. The guy at the garage said that it could be just the sender that's faulty and that alone costs £12. Problem is, if I change the sender and that doesn't work then I would still have to buy the whole thermostat kit for the £84+vat as they don't just sell the stat on its own!

Is there any way that I can check if it's the stat or just the sender that's faulty?

Also if I drive it as it is with the gauge showing 70 degs will I harm (i.e. overheat the engine) or does the stat default to open i.e always sending coolant to the rad? I appreciate that if the engine stays cool I will use more fuel as the ECU will try to increase combustion temperature, but rather that than cook the engine and blow the head gasket.


Any advice much appreciated before I spend £70+ on a part that I may not really need.

[156Chris]

Originally Posted by Starsky

Does that mean that your temp sender isn't working then or is it the actual dial that's duff?

I went to the stealer today and was quoted £84+Vat for the stat

This includes the housing and a new temp sender. The guy at the garage said that it could be just the sender that's faulty and that alone costs £12. Problem is, if I change the sender and that doesn't work then I would still have to buy the whole thermostat kit for the £84+vat as they don't just sell the stat on its own!

Is there any way that I can check if it's the stat or just the sender that's faulty?

Also if I drive it as it is with the gauge showing 70 degs will I harm (i.e. overheat the engine) or does the stat default to open i.e always sending coolant to the rad? I appreciate that if the engine stays cool I will use more fuel as the ECU will try to increase combustion temperature, but rather that than cook the engine and blow the head gasket.


Any advice much appreciated before I spend £70+ on a part that I may not really need.

99% of the time stats fail open and it isn't too much of a problem them running cold, although it does cause extra strain on the engine ...

Also I got the stat for my JTD from Alternative Autos for £65 inc VAT and Delivery ... a stealer wanted £87+VAT for mine

[156Chris]

Just had a thought of a way you can test if it is the sender or the stat ... the ECU turns the fans on at just over 90deg, so go for a good spirited drive around, then stop, when/if the fans come on come this with the reading you get from you sender, if the sender is still reporting 70deg and the fans are on then it's the sender ...

... if the fans never come on it is likely to be your stat ..


... just make sure you do this without the Air Con on as this turns the fans on too ...

[Starsky]

So if I understand correctly:

Have a good burn around then stop (engine still running?)
If the stat is working it should have allowed the engine to warm properly and therefore if I stop (and it has warmed up well) the fan will kick in to help the coolant cool through the rad.
If this happens and the dial is still reading 70 it can only be the sender that's at fault as the stat must have been closing to allow the temp to get up to 90degs+.

If after stopping the fan doesn't cut in, it means that the stat must be stuck open as the coolant never gets up to temperature therefore the sender is reporting the correct temp to the dial.

One question though. Does the temp sender only link to the temp gauge? What informs the ECU of the engine temp?

[156Chris]

Originally Posted by Starsky

So if I understand correctly:

Have a good burn around then stop (engine still running?)
If the stat is working it should have allowed the engine to warm properly and therefore if I stop (and it has warmed up well) the fan will kick in to help the coolant cool through the rad.
If this happens and the dial is still reading 70 it can only be the sender that's at fault as the stat must have been closing to allow the temp to get up to 90degs+.

If after stopping the fan doesn't cut in, it means that the stat must be stuck open as the coolant never gets up to temperature therefore the sender is reporting the correct temp to the dial.

One question though. Does the temp sender only link to the temp gauge? What informs the ECU of the engine temp?

Yep that sounds about right ...

... apparently there are 2 sensors one for the dial and the other for the ECU ... although I couldn't tell you anymore details about this as it isn't something that has gone wrong on my car (and I'm not that much of a geek to go and find out )

[Starsky]

Thanks 156Chris. I'll give it a go tonight.

I bet I need to spend the cash though

[156Chris]

I am a geek, just looked up how the temperature sensor works ... there is a small pipe that carries coolant from the stat to the injection system and it is the injection system that has a sensor to measure the temperature that is then sent to switch on the fans ...


... so I presume that it would be possible for the temperature of the 2 sensors to be reported as being different (although not by much I would assume ...)


... good luck on the Alfa Autobahns tonight that everyone on here seems to drive on

[Starsky]

Originally Posted by 156Chris

I am a geek, just looked up how the temperature sensor works ... there is a small pipe that carries coolant from the stat to the injection system and it is the injection system that has a sensor to measure the temperature that is then sent to switch on the fans ...


... so I presume that it would be possible for the temperature of the 2 sensors to be reported as being different (although not by much I would assume ...)


... good luck on the Alfa Autobahns tonight that everyone on here seems to drive on

Good. That means your test should give me the culprit. If the fans kick in and the temp gauge still says 70 then the little blighter is lying. I should be so lucky though. These things never turn out to giving you the cheap option. Thanks for being a geek. I'll hold off on ordering the stat for just a little longer then.

[longprest]

If you do change your thermostat and btw i got mine from Alternative Autos too make sure you've got a good selection of jubilee clips as some will not refit without special tool, swopped some of mine round as aftermaket clips bigger and fouled battery tray - not much clearance, also note theres two bolts on the back of cylinder head that hold EGR cooler on - not obvious!

[Buzz84]

sounds like mine could be something different as i have the cooling fans turning on and off as the dial fluctuates over and under 70C.

Guess i am goning to have to see if i can see what the other temperature read out says the temp is, which means i have to sort out my laptop cable and software, a topic for another thread maybe!

mine does not move either. only when stuck in traffic. my needle stays about 50 lol.
cant fix it myself and cant pay garage either!!

[Mr Dunamis]

Is this an easier job on a 1.9? Where is the thermostat? why is nothing on an Alfa where you expect it to be? (apart from the wheels and brakes )

[dirtyjohn]

i know.its blimin impossible.im still looking for it.
anyone out there got a diagram showing where this thing is?

[Mark_JTD]

On the 2.4 it's below the battery tray. You can just about see it with everything still bolted in. Not sure about the 1.9, I assume it'll be in the same place?!

Cheers,

Mark