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Sadly after almost 4 years of completely trouble free motoring my TT overheated on the way to Plymouth last Saturday and has blown the head gasket, 12 miles away from completing a 235 mile trip. :(

 

I'm looking for opinions on the best course of action from here. Whifbitz have suggested replacing the engine. I can understand that point of view, is it the best option though? The engine hasn't been stripped to check for any other damage so we don't know if there is anything else more serious wrong.

 

The thing on my mind is that being that it's an auto and it's done a few miles the cost of the repair whichever route I take is most likely going to be uneconomical relative to the value of the car, on top of this whatever has caused the overheating will need to be addressed. Should I just break it? Is there much to break considering the engine is not usable at the moment? I'm not keen to break it as it has been a great car but at the end of the day it has to come down to the economics, I can always get another car...

 

I am a little bit lost as to what to do so any advice would be much appreciated!

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If you decide to repair it the absolute minimum is going to be the head gasket being replaced. This is a fairly labour intensive job on a stock car so would be costly on its own. You may need to add in a head skim, you might as well do the valve stem seals while at it and you would need to find the root cause of the overheating (radiator/thermostat related). Not sure what this will cost but it will have 3 zeros after it regardless.

 

Replacing the engine is straight forward enough for most people, labour would most likely be less than with a head gasket change but you would be running a sort of unknown engine. The engine would cost you about £1000 also before any fitting etc. Given this scenario you would still need to find the root cause of the overheating so that makes no difference to the cost.

 

If it was me I would do a compression test to see what readings you get. I'm not sure how much difference a blown HG would make to those results though. If the compression test results were favourable I would fit a new gasket, refresh the head, change the thermostat and flush out the cooling system. Job total would probably be around £1000-£1500.

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If the head gaskets gone is there any point in doing a compression test ?

All it will do is show which cylinder/cylinders its failed on.

 

The worry is how bad and for how long it overheated for ? Cooked aluminium heads tend to warp and if it has

then it could be scrap.

Toyotas guide i think is a max of 0.1 mm or 0.004 inch, thats pushing it in my opinion.

 

Also as Scott says why did the head gasket fail, water pump, radiator, not enough coolant, etc etc

 

How many miles has your car done ?

Edited by Dnk (see edit history)
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If the head gaskets gone is there any point in doing a compression test ?

All it will do is show which cylinder/cylinders its failed on.

 

It might show if the engine is worth keeping though, if the compression is good across the rest of the cylinders then it might give an indication of the condition of the ones that don't show any compression. It would be a gamble though, hoping that there was nothing else wrong.

 

It's going to be a gamble regardless though unfortunately.

 

2nd hand heads are relatively cheap though, even if his was warped it would be reasonably easy to get another one for decent money.

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Have you tested if it definitely is the head gasket that is leaking?

 

Yeah, that

 

When I had my first Supra, that overheated. This was way before I knew much about cars; I called the AA, and the guy told me that the HG was leaking. A day or so routing around under the bonnet revealed a leaky core plug - plug out, new one in, job done..... think it cost me 34p

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Yeah, that

 

When I had my first Supra, that overheated. This was way before I knew much about cars; I called the AA, and the guy told me that the HG was leaking. A day or so routing around under the bonnet revealed a leaky core plug - plug out, new one in, job done..... think it cost me 34p

 

Whifbitz confirmed what we knew but I will definitely look into what you have said.

 

The car has done around 120k. I wish I could say how long it was getting hot but unfortunately I was on unfamiliar roads, late at night and looking out for speed cameras/where I was going rather than watching the car. It was steaming for what felt like forever after pulling over.

 

It looks like I have three options then:

 

Fix the head gasket and take an unknown chance on anything else being damaged

New engine

Sell/Break as is

 

I've had better decisions to make!

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120k isn't high mileage in my opinion, my cars done 133k now and running sweetly

 

If your car was mine i'd get the head taken off and checked to see if its warped and

pressure tested, then make a decision based on the results.

 

While the heads off you can also check the cylinder bores.

 

The unkown part is why did the h/g fail which you'd still need to find out, check the radiator

and the rest of the cooling system, it could be down to a stuck thermostat.

 

Was the heater working before the problem ? any dampness or smell in the passenger

footwell ?

Edited by Dnk (see edit history)
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If the head gasket is definetly leaking, which is quite rare i think. And your happy with stock power. Id do as suggested and fit a secound hand engine. You could spend time/money on the current engine and may end up in the same situation. There may even be other problems relating to the leakage.

 

Sometimes you gotta learn to cut ya losses, but you gotta make sure the next engine is a good un.

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120k isn't high mileage in my opinion, my cars done 133k now and running sweetly

 

If your car was mine i'd get the head taken off and checked to see if its warped and

pressure tested, then make a decision based on the results.

 

While the heads off you can also check the cylinder bores.

 

The unkown part is why did the h/g fail which you'd still need to find out, check the radiator

and the rest of the cooling system, it could be down to a stuck thermostat.

 

Was the heater working before the problem ? any dampness or smell in the passenger

footwell ?

 

No problems in the passenger footwell - a sign of the heater matrix going?

 

The only problem the car has been having is when I have been starting up from cold and driving off steadily initially the temp gauge would go higher than usual but then come straight back down to it's normal level. After the initial rise the gauge would remain at it's normal level. I can say for certain that for at least 200 miles of my trip that the gauge was in it's usual position.

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No problems in the passenger footwell - a sign of the heater matrix going?

 

The only problem the car has been having is when I have been starting up from cold and driving off steadily initially the temp gauge would go higher than usual but then come straight back down to it's normal level. After the initial rise the gauge would remain at it's normal level. I can say for certain that for at least 200 miles of my trip that the gauge was in it's usual position.

 

When the heater matrix leaks it usually shows in the passenger footwell and you get an antifreeze

smell in the car due to the matrix being in the dash roughly behind where the stereo is.

 

The temp should climb to its operating point and stay there, not go up past it and then back down. Possibly a problem with the thermostat sticking.

 

Before you do anything you need to find out why you have the overheating problem.

Get the rad out the car and checked, i'd also get the stat out the engine and check that too.

A coolant hose could have a leak.

Was the heater working before the problem and blowing hot air ? They can sludge up

as well as leak.

How olds the coolant, has it ever been changed, is the rad the original, is the rad cap the

original.

Edited by Dnk (see edit history)
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No problems in the passenger footwell - a sign of the heater matrix going?

 

The only problem the car has been having is when I have been starting up from cold and driving off steadily initially the temp gauge would go higher than usual but then come straight back down to it's normal level. After the initial rise the gauge would remain at it's normal level. I can say for certain that for at least 200 miles of my trip that the gauge was in it's usual position.

Sounds like thermostat opening bit too late, make sure HG is really leaking.

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