Unusual Overheating

My cooling system isnt working properly. Usually when im not running the A/C the temperature reaches 100'C and on occasions 130'C but when the A/C is on the the fans work more frequently so the coolant temp goes to the middle & stays there... but i still can smell some sort of overheating odor from the engine bay & there is too much heat coming.. One of my radiator hoses has formed a bulge on it... My water pump is new & my coolant level stable...

The hose has collapsed inside and is blocking the flow. The bulge is either pressure or lump of inside hose lining thats formed a block.

All my Fiats have done this sometime...

Thermostat is buggered I would say but if it's causing a bulge that's added pressure so could be the start of your head gasket. Get the thermostat replaced ASAP I wouldn't run the car till that's done. It maybe to late but maybe not so don't take any chances. If the head hasn't gone and you leave it in this condition it will go.

so i could replace the hose along with the thermostat & all is done? Hope no major damage is done to the engine..

I do need to change the gasket though as its having a a very minor oil slime coming out...

Very minor oil slime comming from where? and if you know the headgasket has gone your answering your own question.

The headgasket is where the slime is coming from.. how bad can it be?

That's why it's overheating then, gasses are getting into the cooling system causing the pressure and also causing the overheating. You can't drive it till the head has been done or you may cause some serious damage.

Sorry to hear about the overheating problems ROJ, could be partly due to the fact that it's about 45C outside (in the shade)? I have problems in the summer too.... In the winter temp sits happily at 1/4 but in the spring during the day would be at 1/2 to just over (with the air con off) at the moment with the air con on it would eventually start to climb towards the 3/4 mark but if I switch the a/c off ot drops to 1/2.

I have found myself keeping an eye on the temp and switching it off untill it gets too hot in the car and then switching it back on...

I used to have a Lotus Elan here for many years and found that I had to do the same with that too. Just not designed for this kind of heat!

So Have never really worried too much about the temp increase... But there again I dont have fluid leaks, bulging water hoses or slime at the head gasket (or not yet)!!

Anyway, not sure of a normal price for a head gasket set but there's one on ebay for £60. Mmm, could it be someone on here selling it???

http://cgi.ebay.co.uk/HEAD-GASKET-SE...3286.m14.l1318


Hope this helps

^ thats the complete gasket set ur talking about.. Its available here in the UAE but im getting the head gasket only for AED 60.. Some parts are really cheap at my place...

You will need to skim the head, so look for a good engineering workshop. If you don't skim the head there is a good chance that you will have the same problem pretty quickly after.

Wait a min... The head gasket i was refering to is the tappet cover gasket.. Sorry for such confusion.. My head gasket is okay...

Thermostat is in good condition.. Just changing tap cover gasket with fan sensor on the thermostat.. Im thinking of cleaning the camshafts as the engine the pretty dirty from the inside.. The tappets need some checkup also...

No cambelt is needed to be removed during this process? or is it okay to reuse the belt with its bearings and tensionser as its still brand new?

Tappet cover=rocker cover gasket, Head gasket=cylinder head off i.e. top of the engine.

So back to Square 1......

If the thermostat is OK (did you check it with boiling water to ensure it opens or just think it looks OK?) you need to find where the pressure is comming from.

As rustbucket initially said check the hose to see if it's collapsed inside blocking the flow. If that is OK then I would have the cooling system pressure tested to make sure your head is OK as to me it sounds likely that the cylinder head gasket has gone.

So HGFs are usual on 16v 1.8 engines? Mine is a 00 model & has 135K km done on it so far...

Head gasket failures are possible in any car but less so if the cylinder head is cast and not alloy (but doubt that any car these days will have a cast head).

The biggest cause of failure is overheating, once the alloy head overheats it begins to warp. If the head warps by the smallest of fractions it can cause a gasket failure due to the ammout of pressure they generally have to withstand. So if your car has recently overheated it MAY be possible that the head has suffered as a result. The usual signs are coolant in the oil or oil in the coolant producing the foamy scummy substance in either the oil system or coolant system. However the gasket or head itself can fail at any point so you may find that oil or coolant is being forced into the cylinder chamber where it's more difficult to initially detect till you get loads of smoke or steam comming from the exhaust and starts to run on only three cylinders.

The dangers are that the overheating can then cause further damage and even engine siezures in the most extreme of cases and/or where the drivers ignore the signs and continue to drive.

The reason for mentioning the head being skimmed is that if you don't there is that likely hood that the head is already warped even by just a fraction so if fitting a new gasket without being skimmed it will hold briefly due to a new gasket being fitted but will eventually weaken till the gasket gives up once again usually within 6-10 months.

Hope this makes sense, the pills are now starting to take effect...

In short check everything oil/coolant/hoses/thermostat to find the cause of the overheating. IT MAY NOT be the gasket but if the original cause isn't found it may well be soon.

Thanks alot for your help AlanD... Really appreciate it.. i hope i didnt get you much into these situations: ""

For now ill leave the car parked, im getting the complete gaskets kit & replacing them along with cleaning up all the oily filth inside the engine, will not replace the variator for now as ill wait for another day for the next cash flow..