Technical cooling

[JOHN COOPER]

Can anyone help with on how to bleed the cooling system on my croma 150 jtd.

 

[Radlet6]

Hi John

Attached is a document which outlines how to change the coolant and hence sets out the procedure for refilling and bleeding

 

[JOHN COOPER]

Thanks for the info sorry its a bit late, but my croma is driving me round the bend. i have water temp gauge thats up/down like a yoyo and no warm air its not over heating has anyone had this problem

 

[Doofer]

What does the temperature do - does it ever go above halfway on the gauge?

I was a bit worried when I first got mine. My old car used to warm up, get to halfway and stay there. My Croma seems to get to about a quarter, then waggle up and down to halfway depending on the driving. I drove up a long 1:4 hill in second gear on a hot day recently and got it just over half - the highest I've seen it.

If you have climate control then it's not very good - search for previous posts. "Full Auto" doesn't seem to work properly when heating on my car, but it's fine if you manually set the vent positions and let it control just the fan speed. In the summer it seems OK though.

 

[DoIDon'tI]

Guys, I hate to spoil your day but it sounds like the thermostat on both your cars is sticking. This is a known problem on the JTD engines if you have a look on the Alfaowner and Vectra-C forums. The car should get to just over halfway on the gauge and stay steady there. It might take a bit longer in very low temperatures but will still get there. The heating will not work properly until the car is fully warm.

HTH.

 

[Doofer]

Thanks - I'm very glad to hear that there is a problem, as then it can be fixed! The heater's always been useless.

Will read up further...

 

[JOHN COOPER]

Hi thanks mine warms up stays steady for a time and then it goes right to the top and then drops back to normal,when you check its not overheating and the fans are on all the time. engine temp is 70 rad and all hoses around 30, getting fed up with it now as our dealer have no idear to what wrong.

 

[DoIDon'tI]

Could be the coolant temp sensor on the engine - intermittent breakdown giving spurious readings. What timescale are you talking for the needle to go to max i.e. is it a rapid movement of the needle up and down, also are you getting any 'excessive coolant temperature' messages on the dashboard information panel?

Also may be worth checking the connector to the temp sensor for water ingress and the associated wiring for damage.

Bear in mind that this could still be a thermostat issue i.e. engine core temperature builds up to a high value, the thermostat finally opens and normal operation resumes. If this is the case it will only do it once for each cold start. Does the temperature gauge continually fluctuate or is it random? Just trying to get a more detailed feel for the proble.

HTH.

 

[JOHN COOPER]

Its random some days its fine then in one jurney it will do it many times each time it brings up'excessive coolant temperature' temp needle move steady from normall some times faster.

 

[notorious]

I just realized in the last 10 days or so that my temp gauge has been fluctuating a lot between the 2 double marks on the gauge only reaching halfway mark under heavy load(say 150kmh for extended time on highway or uphill). It doesn't stay at halfway point and it never goes over the half point and there are no messages or fault codes. Outdoor temperature was anywhere from 0 to 15 Celsius. Is my thermostat sticking open ie. slowly failing and is my fuel economy suffering due to this? I am almost sure last year it was always at halfway mark. Should I have it changed? I will check the part prices tomorrow.

 

[arti_abarth]

I just realized in the last 10 days or so that my temp gauge has been fluctuating a lot between the 2 double marks on the gauge only reaching halfway mark under heavy load(say 150kmh for extended time on highway or uphill). It doesn't stay at halfway point and it never goes over the half point and there are no messages or fault codes. Outdoor temperature was anywhere from 0 to 15 Celsius. Is my thermostat sticking open ie. slowly failing and is my fuel economy suffering due to this? I am almost sure last year it was always at halfway mark. Should I have it changed? I will check the part prices tomorrow.

you should and need to change the thermostat
when my stat went i was getting only 32mpg instead of about 40
also your engine runs cooler and ecu may delay dpf regens and that will cause some expensive problems

 

[bobbyblue]

John, I hope it's not this but I had exactly the same symptoms on my Croma 1.9 8v late last summer, the car would start to show a slightly raised temp guage reading, this was intermittent at first and would be fine for days then would play up for a few more then go alright for a few days again. Eventually it got bad enough to put the 'Excessive coolant temperature' warning up, the engine did not feel as though it was overheating though. Classic sticking thermostat I thought and went out and bought one for £63 from my local dealer (includes the housing & temp sender), this was a bit of a sod of a job but completed o.k. This did not cure the problem however, I got suspicious when I put the heater on as the weather turned a bit cooler, it was useless and blowing cool air. I finally tracked the problem down to the impeller having come loose on the water pump shaft. The impeller is plastic and pressed onto the shaft via a cast- in bush, when I removed the pump I could spin the impeller on the shaft. This is a common problem with cars of the mid 2000's as it was another cost down exercise. I went to my local motor factor and bought a new pump for £27...with a metal impeller, dread to think what it costs at the main dealer and fitted it with no further problems since. By the way, the bearings on the old pump were on their way out as well, this was at 46,000 miles so I changed the timing belt while I was at it. I wish you the best of luck.

 

[Doofer]

Yours sounds just like mine was. It was getting above cold, but never getting to the centre unless under heavy load.

My thermostat was faulty, as I was correctly told by DoIDon'tI earlier in the thread. I replaced the thermostat last summer and the car's utterly transformed. The heater never worked properly, and the engine was permanently clattery as it was too cold. Now the climate control works perfectly on full auto mode, the engine's quiet and all is well.

Be warned though - you won't believe the size of the job of changing the thermostat on one of these things. It's a complete unit, with numerous inlets and outlets. The full procedure is in eLearn, including coolant drain and refill etc. You'll also need a full box of jubilee clips, as those fitted are chuckaway single use types. You'll also need lots of time/patience and some spare skin on your knuckles.

Search the Croma forum for lots of info from myself and others.

 

[notorious]

Thanks all, I will be getting it done soon. I ordered the thermostat and rear discs and pads. Prices in Serbia 50 eur thermostat, labour 30 eur, rear discs 55 eur, pads 30 eur, labour 25 eur.
Cheers