A Question for those that know about Cars (and fixing them)?

cambsno

cambsno

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Don't worry, I will be getting the car looked at by a mechanic in the next week or so, but in the meantime it would be great to get some opinions on what may be wrong with my car (and know if its likely to be tens or hundreds to put right!

Car - 2004 Ford Focus 1.8 petrol. Had it for 8/9 years and been super reliable with pretty much only wear and tear items needing replacing. For the last 2.5 years it has pretty much only been for going to station/work (10 miles each way) and the odd local trip.

Problem - Around 6 weeks or so ago I noticed that the heaters were not pumping out heat! Well, they were but only after driving for 15 mins (as opposed to 5 mins) and even then, not that hot! More recently I have noticed that heat is not even lukewarm some 20 mins later. The engine temp gauge had always been in the middle when driving and when I go off in the morning gets there within 4/5 mins and stays there. Last week I went on a longer trip than normal and noticed the gauge was heading towards the red. If I eased back and drove at 55/60 it tended to be in the middle - push onto 75 and after 10 seconds or so would move to the edge of the red, ease back again and 10 secs later it would go back a bit (or to the middle). Today I was in town an din stop start traffic and the gauge actually hit the red - when moving at 50 it came down to mid/two thirds along. When in the red I tried the heaters and initially a big burst of warm air came out (for about 5 secs) then it was barely lukewarm.

Any ideas? It drives perfectly, no smells or noise but the heating is obviously not working and the gauge seems to suggest overheating when car is warm .
 
I'd go with the thermostat, a cheap fix unless you carry on playing head gasket roulette with the throttle
 
Coolant level? I assume you've checked it and it's between the Min & Max marks on the side of the expansion tank?

If it's OK, then the other 2 guys are probably right - thermostat. If you have to get a "proper" mechanic to change it, it would be a pretty cheap job on a Focus, I'd imagine.
 
Coolant air lock, or not enough of it, depending on the system would be my first port of call.
 
From my minimal knowledge I'd go with thermostat too....I had one that wouldn't open and let coolant through. Easy peasy to change.
 
Would you not constantly loose coolant if the head gasket was going (as well as having peanut butter like gunk on your oil filler cap)?....( Asking for my own knowledge really)
 
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Possible causes, in order of simplicity to fix:

Coolant level (check where it's going if it's low though)
Thermostat
Head gasket

With the aid of a Haynes manual, all of those should be DIY-able if you are worried about cost (assuming you have a few spanners etc). The only bad bit about head gasket replacement is cam belt replacement, if your car has a cam belt. That's a job I really don't like on any car. Bring back chains.

antihero said:
Would you not constantly loose coolant if the head gasket was going (as well as having peanut butter like gunk on your oil filler cap)?....( Asking for my own knowledge really)
Click to expand...
Normally what happens is the seal around the combustion chamber fails into the water jacket. This will (again, normally) lead to air in the water system and water in the combustion chamber, which will eventually lead to steam coming out the exhaust and overheating - not usually through lack of coolant but because all the air in the cooling system stops it working properly. It's quite possible for a car which has the correct level of coolant to overheat due to a blown head gasket.

If the steam mixture starts blowing past the piston rings, water gets in the oil and you get the mayonnaise like substance (an oil and water mix) under the oil filler cap.

I used to run a (completely standard) Hillman Imp as my every day car, so I have extensive experience of head gasket failure and replacement. One of the first symptoms was the heater stopping working despite the temperature gauge going up - caused by airlocks in the long pipe runs from the back of the car to the heater matrix.
 
antihero said:
Would you not constantly loose coolant if the head gasket was going (as well as having peanut butter like gunk on your oil filler cap)?....( Asking for my own knowledge really)
Click to expand...

No - if the seal has broken enough to let the very high pressure combustion gasses through but not let water seep through. This is what happened on both my Celicas - one due to overpresusre in the cooling system caused by a blockage of solidified brown sludge (Change your coolant regularly and don't just use water!) and the 2nd because I allowed it to run far too lean, cooked the engine and killed the HG. Both were still driveable though the temp gauge would randomly go through the roof as the combustion gasses replaced coolant in that section of pipe that the sensor was in until it worked it's way out of the system via the rad cap. Because the system was self bleeding this was possible, had the system not been self bleeding it would have airlocked, overheated and wouldn't have lasted very long at all!
 
Update. Checked the coolant and empty. Topped up with water and then saw water dripping underneath. Seemed to be coming halfway or 2/3 the way up the engine to the right of centre as u look, seemed to be a tube connecting engine to radiator close by.

Wife taking in later.
 
Just for future ref.

Normal-high temp gauge but little to no heat from heater is usually coolant level. The heater uses the coolant to heat the air. If there is no water you'll get very little heat. If the thermostat is sticking closed then you may get very hot air but a cold temp gauge or cold air but a normal/hot temp gauge.
 
mattyg said:
Just for future ref.

Normal-high temp gauge but little to no heat from heater is usually coolant level. The heater uses the coolant to heat the air. If there is no water you'll get very little heat. If the thermostat is sticking closed then you may get very hot air but a cold temp gauge or cold air but a normal/hot temp gauge.
Click to expand...

Thanks - was confused why the car was overheating yet stone cold out the vents, but as is obvious, i know naff all about cars.

Anyway, wife took to kwik fit and all seems ok (they didn't charge despite taking it round the block a few times!). I topped up coolant and it looks like it was an airlock, as heating fine now!
 
Could be a cut in one of the hoses often near a jubilee clip

I would make sure you have a few bottles of water in the boot incase and check water level every few days for a while.

I had a similar and it was a crack in thermostat housing that slowly leaked away my coolant.

make sure when you fill it you maintan a good miz of anti freeze.
 
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