Re-post...car repair issues

Joe_Horner

benham3160 wrote: »

I bang my head on the desk at any mechanic worth his salt who wouldn't renew a thermostat after a "spontaneous" HGF.....

For £10, it's just something ya' do....

Regards,
Andy

Like I said, more a shoe-string DIY bodge for a banger than something you'd expect from a main dealer. Although most of the banger mechanics I've known would at least have the sense to leave the stat out completely if there was any doubt

noofighter

Mikey72 - seems like the issue with an engine over-heating really can't be solely caused by a thermostat, as all that's going to do is allow the fan to blow, which in itself is only really any use when the car is stationary with hot engine. From what you've said, for something like a HG block to warp, there would have to be more issues than that; it would have to have been compromised at the point of the initial problem 9 months ago to then warp or have any subsequent problems, heat alone cannot cause a perfect block to have any issues?

I need to also double check that there have been no further leaks from the work done on the HG at their point of repair; surely that would just be downright negligence? If the HG is cracked and water is getting in, which caused the cylinders to fail in the first place (which was the gyst of the initial repair), then surely they should be checking not only the thermostat but also the block for any damage that may have been caused? Again, seems like a half-!!!!!d job on the part of the dealer; the analogy I used was if I'd fallen off a wall and hurt my leg, I wouldn't expect A&E to only repair a broken ankle before sending me limping home with a fractured tibia...

Does this sound about right? Or can a failing thermostat really have a profound effect on the engine anyway? As I said, there have been no internal indications that anything was wrong; don't recall the fan not cutting in, the warning light never appeared (though it did moments before the original HGF), like I said it was only through a local garage investigating failed air con that these bubbles in the radiator were spotted.

Can I also tap anyone's knowledge here on why this dealer would look at the radiator when fiddling with my air con?? This is the one complete mystery of it all - why my air con is included in any discussions. I'd love a theory or two on why this was the case. The story on that is that, pre-HGF fail, my air con stopped working on a long journey. I opened the bonnet, checked the radiator and it was dry. Upon filling the radiator with deionized water, the air con then started to work again. No-one can give me an answer; all I get is repeatedly told "the two are separate".

mikey72

One possible way for the headgasket to fail is between the cylinder and a waterway. It can fail in such a way as instead of water leaking into the cylinder, the combustion gases pressurises the water system. This doesn't cause the engine to overheat as such, but it will over pressurise the cooling system, and blow the water out of the header tank, through the cap. If the original failure damaged the block, any repair wouldn't last long, before it went again. It would be noticed under the bonnet, running the engine, as you would see water bubbling out, and some cars do indeed shut off the air con when they start to overheat to reduce load on the engine.

noofighter

mikey72 wrote: »

One possible way for the headgasket to fail is between the cylinder and a waterway. It can fail in such a way as instead of water leaking into the cylinder, the combustion gases pressurises the water system. This doesn't cause the engine to overheat as such, but it will over pressurise the cooling system, and blow the water out of the header tank, through the cap. If the original failure damaged the block, any repair wouldn't last long, before it went again. It would be noticed under the bonnet, running the engine, as you would see water bubbling out, and some cars do indeed shut off the air con when they start to overheat to reduce load on the engine.

Yes, the air con shut off was the only tangible suggestion I've had so far (from The AA). Not sure, though, as it wasn't working when I drove the car away from the dealer after the original HGF repair job. Very odd; suffice to say, I have never had anything like an explanation from the dealer.

I guess we need to draw this to a close now, though like I say the information from everyone has been excellent. The question is how do I approach this back with the dealer? Timeline is;

May 2011 - HGF
May/June 2011 - HGF repair, £2300 costs, cylinder heads replaced and refitted
June 2011 - Air con fail, re-gassed then working
April - Air con check revealed 'bubbles in radiator' - suspected HG issue
April - advised of issues with thermostat, also issues with HG block. Cost of repair - either new engine or £750 to work the block back to working state
May - ???

Do I continue to hold the dealer accountable and ask that as a bare minimum labour is free of charge?
Do I hold out for a complete foc repair as they are almost certainly responsible for the failure?
Do I pay out the £750 and consider small claims court afterwards?

I do need the car back, as the Micra I'm driving isn't going to help for my family of 4 heading to Dorset in a couple of weeks!! All suggestions appreciated, understand that it's just an opinion and no-one is accountable for my actions other than myself.

forgotmyname

If the engines thermostat doesnt open the hot water in the engine cannot escape so it just gets boiled until something gives. Headgasket or waterway etc.

That has no bearing on the aircon. Except a sensor may think the engines hot and say sorry no you cant switch the aircon on.

You REALLY need an independant mechanic to check to see what the issue is.

1/2 hour, 1 hour tops. They will be able to check the thermostat or get a gas sniffer on the coolant etc.

A stuck thermostat will boil the water and cause bubbles. If you keep/kept running it like that then you could do/have done some serious damage.

mikey72

forgotmyname wrote: »

If the engines thermostat doesnt open the hot water in the engine cannot escape so it just gets boiled until something gives. Headgasket or waterway etc.

That has no bearing on the aircon. Except a sensor may think the engines hot and say sorry no you cant switch the aircon on.

You REALLY need an independant mechanic to check to see what the issue is.

1/2 hour, 1 hour tops. They will be able to check the thermostat or get a gas sniffer on the coolant etc.

A stuck thermostat will boil the water and cause bubbles. If you keep/kept running it like that then you could do/have done some serious damage.

It'll raise the head temperature though, and the op has said the gauge isn't going up.