Ask an expert
Hi, a couple of months ago I took my car to a mechanic to get repaired because it was overheating and using a lot of water. I also asked them to do a service/oil change.
They advised that they carried out a TK test to check for a blown head gasket which was clear and that they did a pressure test on the cooling system for leaks - presumably with no issues.
Next they removed the thermostat and found that it was faulty - however they had just removed the old thermostat and reassembled the engine without putting a new thermostat in. I was not aware at the time that they had done this.
When they rang to advise of the results of engine check and investigations, they let me know about the thermostat but didn't ask whether I wanted to replace it or not - I had assumed that they would put a new one in. Why would they not put a new thermostat back in?
The car ran fine for a while but has since started overheating again. After taking it to a new mechanic recently it has been found that the head gasket has blown. The new mechanic discovered that the thermostat had been removed.
A couple of questions -
* Is it normal to fix a faulty thermostat by simply removing it?
* To me it seems like a pretty shoddy job by the first mechanic - is it worth making a complaint and would they be liable for any damage?
Hi there,
I would suspect the writing was on the wall for your engine at the first instance where the vehicle was using a lot of water and running hot. If the thermostat was stuck shut, the vehicle would overheat in minutes and all the water would be be blown out of the overflow, as evidenced by steam everywhere.
A TK test is a quick easy check for combustion gasses in the cooling system, but it is not the be all and end all of headgasket fault finding.
By removing the thermostat, they have bought you some time by reducing the cooling system pressure and slowing the water leaking past the headgasket breach. Because if there were no external leaks present and the vehicle was using water (but not blowing it out everywhere)- it would be a high chance that it would be internal, via blown headgasket.
The workshop should have really informed you of what they had done ( a temporary get out of trouble remedy), and/or recommended a more in depth cylinder leakage test to further check for a blown headgasket by someone more specialised if this was not something they felt they could do.