[Unkle Munkle]

Hi all,

When I got my 156 1.8 TS, the temperature gauge barely moved above 50 degrees.

It's been fitted with a quality thermostat (not a nasty Circoli Eurocarparts one that I've heard nightmares about!). The temp gauge fluctuates slightly but, generally, it's running at 70 degrees or just above. I've been told (in no uncertain terms) that is should be running at 90 degrees and should stay there.

I've got another post about fuel economy on here and am wondering if there is still an issue. I'm going to get it 'plugged in' on a multiscan ECU to check the actual temperature to establish whether the thermostat is opening up at the right temperature.

If the car is sitting still, it will climb to 90 degrees and the fan cuts in just above this temp as it should. A bit baffling really as the temp gauge wasn't working at all and now it sort of is but, from what I'm told, is not reading correctly! So how do you check on a multiscan if the car is idling - as the chances are the temp will climb to 90 degrees and everything will be reading correctly! Getting a bit hacked off with this and hope it won't be one of those ongoing issues!

Not sure what else to check unless the brand new thermostat is faulty (seems unlikely). The car has new pink paraflu antifreeze and has had a new radiator at some point not long before I purchased it!

Any thoughts / views / experience of this appreciated!

 

[scottyf]

If you ask me unless your sender is completely fubarred then it would be odd it would read 90 ish and over fuel.

You've probably got leaky injectors if you ask me...
Or a MAF that's causing it to over fuel by saying there is more air than there really is.
Or a lambda that is reading lean when its really not.


However using multiscan you can select coolant temperture in real time and it will show it.

Thing is even if its reading higher than it should be leaning out the mixture anyway.


When the car first starts from a cold start its like an old carb car with the choke out. Soon as it gets past 70 degrees it starts leaning out the mixture.



Unless...
The engine health is down (Ie compression) which would mean you use more fuel. Compression check can give a basic reading of engine health.

 

[alfizta]

all indicates a faulty new thermostat to me, but, as advised, plugin MES first to see if dash and ecu temps match.

 

[kandlbarrett]

A thermostat can open early and with the car moving it will not get to temperature. With a failed thermostat (even stuck fully open) and the car left stationary you are right that it will eventually climb to 90 degrees or above and the fan will cut in. With the car stationary the fan is doing the job of regulating the temperature much more than the thermostat.

On thing worth trying is to start the car from cold and let the car climb to temperature but keep feeling the top radiator hose at the radiator. It should suddenly get hot (too hot to keep your hand on) as the thermostat opens rather than slowly warm up.

However, this is not a perfect test. While a lot of thermostats fail open and cause the temp to rise very slowly some fail in a way that they are closed but open at a lower temp than they should. To the inexperienced this can give the impression that the thermostat is working correctly.

Perhaps you might want to buy one of these:-

http://www.ebay.co.uk/itm/Digital-I...183976?hash=item2c8f816928:g:1mQAAOSwGvhT4ITY

and use it to measure the top hose temp when the thermostat opens. I seem to recall the thermostat for the 156 is 85 degrees so it should get a rush of heat and stabalise around that temperature. i would expect it to remain quite cool then very quickly climb to that temp and then fluctuate between about 85 and 95 degrees.

If you use MES then you would expect to see the same thing.

To me it sounds like you have a combination of thermostat failure and, possibly, engine temp or gauge failure.

 

[Unkle Munkle]

OK - the temp gauge didn't work at all before the new thermostat was fitted. It just sat on 50 degrees until I left it idling. It then climbed to 90 degrees and the fan cut in as normal. With the new gauge, it is definitely behaving differently (or better) in that the gauge climbs to the line between 50 / 90 degrees. I assume this is 70 degrees. I don't monitor it all the time as I need to concentrate on driving but it either sits here or goes between the line and 90 degrees. Again, leave it to idle and it climbs to 90 degrees when the fan cuts in.

I wonder whether it would be worth getting a new temperature sender - any ideas which is best or recommended?

If it had been running with a shot thermostat for a while, could it have knackered the temp sender?

I don't think there's anything majorly wrong with the engine or car as it all feels really nice. The engine is as smooth as silk, revs nicely and idles perfectly. I'm just concerned that I'm not getting the best MPG. I'm fairly competent and can check most basic things.

A local indy has said he'll run a multiscan check on it FOC for me which is great.

I can get him to check the engine temp and lambda operation. Is there anything else I should ask him to check to eliminate any faults or further parts I need to replace?

The car has wanted for nothing all its life. It's had a new radiator and a replacement Bosch MAF fitted during its life. It's only done 48,000 miles too.

Thanks!

 

[gazza82]

I'd get a new sensor .. most of the usual Alfa parts outlets probably stock them .. AlfaShop, AlfaWorkshop, EB Spares, AlternativeAutos (ebay mostly now), Shop4Parts (AO discount!) ... simply screw into thermostat housing.

you might find one at EuroCarParts or GSF but don't hold you breath ..

ECPs adverts say "Any part for any car" .. just not the one you want when you want it!

 

[Unkle Munkle]

I'd get a new sensor .. most of the usual Alfa parts outlets probably stock them .. AlfaShop, AlfaWorkshop, EB Spares, AlternativeAutos (ebay mostly now), Shop4Parts (AO discount!) ... simply screw into thermostat housing.

you might find one at EuroCarParts or GSF but don't hold you breath ..

ECPs adverts say "Any part for any car" .. just not the one you want when you want it!

Yes, for a relatively small outlay and an easy job, it's got to be worth a try I guess. I asked about a particular make as I wondered if there was a make/version I should avoid...

 

[Unkle Munkle]

A thermostat can open early and with the car moving it will not get to temperature. With a failed thermostat (even stuck fully open) and the car left stationary you are right that it will eventually climb to 90 degrees or above and the fan will cut in. With the car stationary the fan is doing the job of regulating the temperature much more than the thermostat.

On thing worth trying is to start the car from cold and let the car climb to temperature but keep feeling the top radiator hose at the radiator. It should suddenly get hot (too hot to keep your hand on) as the thermostat opens rather than slowly warm up.

However, this is not a perfect test. While a lot of thermostats fail open and cause the temp to rise very slowly some fail in a way that they are closed but open at a lower temp than they should. To the inexperienced this can give the impression that the thermostat is working correctly.

Perhaps you might want to buy one of these:-

http://www.ebay.co.uk/itm/Digital-I...183976?hash=item2c8f816928:g:1mQAAOSwGvhT4ITY

and use it to measure the top hose temp when the thermostat opens. I seem to recall the thermostat for the 156 is 85 degrees so it should get a rush of heat and stabalise around that temperature. i would expect it to remain quite cool then very quickly climb to that temp and then fluctuate between about 85 and 95 degrees.

If you use MES then you would expect to see the same thing.

To me it sounds like you have a combination of thermostat failure and, possibly, engine temp or gauge failure.

I tried this a lunch time from a cold start. The top hose remained cold for about 10 minutes before it suddenly got hot (too hot to touch). The temp guage had risen to between the line and 90 degrees before it did this. Once the hose became hot, I check the temp gauge and it had dropped to the line between 50 / 90 degrees again before climbing back up to 90 degrees. The fan then came on for about 30 secs - 1 min and the temp gauge sat just below 90 degrees. However, I know that if I drove off, the gauge would drop back to the line between 50 / 90 degrees. There is some conflicting reports as to what temperature this line represents. My logic would say 70 degrees but have been told it could be 80!

Not sure if this helps with any further diagnosis prior to being plugged into the multiscan. The thermostat was only renewed a month ago and the gauge is definitely working and doing something now whereas before it just sat at 50 degrees when driving along!

 

[scottyf]

Sounds to me like the thermostat is doing its job.

 

[alfizta]

I can all be right, but mine doesn't behave exactly like that.

at first warm-up from cold and cruising, temp rises to 90 and something degrees. as the stat opens, gauge temp drops to not less than 85 ºC (halfway between the unmarked line and 90 mark line), then rises again and stays almost at 90 ºC all the time.

is it possible that you have fitted the wrong stat? which make and part number is it?

the way you describe looks like the stat is opening too soon. anyway, each alfa is an alfa in its own way

 

[kandlbarrett]

One thing to be aware of is that the 156 (unlike 147) temp gauge is not damped. The 147 will sit on 90 degrees for any temp between about 80 and 100. If you drive a 147 with MES reading live you will see the temp on MES fluctuating like mad between those temps but the gauge doesn't fluctuate. The 156 gauge working correctly is NOT like that and shows instant temp so will fluctuate. How much it fluctuates will be dependent on a lot of things including thermostat.

It does sound like yours is showing a bit low temp but that could be sender, gauge or thermostat.

Finally my experience with temp readings on the 156 is limited and I am much more experienced with the 147.

 

[Unkle Munkle]

I can all be right, but mine doesn't behave exactly like that.

at first warm-up from cold and cruising, temp rises to 90 and something degrees. as the stat opens, gauge temp drops to not less than 85 ºC (halfway between the unmarked line and 90 mark line), then rises again and stays almost at 90 ºC all the time.

is it possible that you have fitted the wrong stat? which make and part number is it?

the way you describe looks like the stat is opening too soon. anyway, each alfa is an alfa in its own way

The stat was supplied and fitted by MDZ Italtec and is a good one. They wouldn't fit the Circoli Eurocarparts one I supplied as they say they're rubbish so I'm confident the stat is good quality and working, hopefully. I'll get multiscan results tomorrow or next Sat from a very helpful chap up the road...

 

[Unkle Munkle]

Had the car checked on a multiscan today. The car runs at 87 degrees and the temp gauge shows 70. It's all running fine so will try a new sender that fits into the stat. If that doesn't work, I'll forget it as a happy in the knowledge that the stat is working as it should.