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Mike, VW Technician
Category: Volkswagen
Satisfied Customers: 39198
Experience:  Tech Expert
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I have a VW T5 1.9 the coolant indicator light comes on after

Customer Question

I have a VW T5 1.9 the coolant indicator light comes on after driving for a short time and then stopping and restarting. the coolant level drops in the reservoir but when the cap is removed the water pushes back into the reservoir sometimes the coolant is very foamy, this happens even if the van has been left over night and the coolant is cold. I have removed the stat to see if that made a difference but it doesn't have also made sure there are no air locks, changed the cap the water pump appears to be circulating the coolant. the van does produce some white smoke when first started in the morning
Submitted: 4 years ago.
Category: Volkswagen
Expert:  Shantal-Mod replied 4 years ago.

I'm Shantal and I'm a moderator for this topic.

We have been working with the Experts to try to help you with your question. Sometimes it may take a bit of time to find the right fit.

I was checking to see if you had already found your answer or if you still need assistance from one of the Experts.

Please let me know if you wish to continue waiting or if you would like for us to close your question?

Thank you,

Customer: replied 4 years ago.

I have not yet found an answer to my question and still need assistance

Expert:  Mike replied 4 years ago.
Hello and Welcome..

My name is MIKE - Im happy to help / advise - Sorry to see you have had a wait..

Before we progress with this - can I just ask - has the van / engine overheated on you at all?

Too - does the temp gauge show it running hot at all?

What mileage do you have?

Rgds, MIKE.....................................
Customer: replied 4 years ago.

the engine has not overheated the temp gauge never goes higher than 90 and the van has 135000 miles



Expert:  Mike replied 4 years ago.
Hello there Phil..

Thank you for your reply and further info..

Ok - well - given the symptoms you describe - and this being the engine it is - I have to tell you that these do suffer with failed / or failing water pumps.. What actually happens is the impeller on the back of the pump , its made of plastic basically, and they break up- they can break altogether and then the engine overheats - or, they can break and come loose on the spindle which means it will continue to pump water round - so it wont overheat - but its not sufficient to keep the cooling system in proper working order...
So thats one and probably the main consideration here - Given the mileage - its a big possibility combined with the symptoms you have... so that needs to be checked / changed .. You have to rule that out at least ...or of course, thats the issue confirmed when its checked..

On these engines, they do pressurise a lot - so its not unusual to get back pressure in great measure - and its normal for the coolant to drop and rise as you describe - any engine will do that if you undo the cap like that ... so thats ok..

Now - if the water pump is ruled out, and you still have the problem - then you most likely have either a leaky head gasket and / or , a porous head.. cylinder head.. Both of which do happen on these.

Of course this entails a lot more work so it would need proper tests next before carrying out such work. Most good small type garages have test kits for these issues... one such kit should you wish to do it yourself is HERE.. click the link.

It doesnt take much of a leak at all in the gasket or head on a diesel engine because of the extremely high compressions on a diesel as opposed to a petrol engine - a petrol engine can "get away" with this - but a diesel will pressurise the cooing system a lot more - giving what you have there.

That will tell then where the fault lies thats causing your problems with this engine Phil..

Let me know if you need anything else-

..>> .Meantime..............Please do click on the "OK/ Excellent ratings" for me as that's how Im credited for helping you - Thank you in advance for that...

You can and are most welcome to get back to me anytime you might need - clicking the OK ratings does not close you out at all..

Rgds, MIKE

Expert:  Mike replied 3 years ago.
Hello again Phil -

Im just checking to see if I can help you anymore in addition to the above as I have not heard back from you at all after you viewed my answer for you . By all means get back to me if you need anything else...or.. if we are done at least for now, please do click on the "OK ratings" for me now at this point - for which I thank you .

Kind rgds, MIKE.