Technical Headgasket or any other possible cause?

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Technical Headgasket or any other possible cause?

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My gfs dad has just bought a '97 1.4 bravo. It wasn't till he was driving it home he found an overheating problem so called me over.
Car was cold when i got there, but i noticed the coolant bottle was wet as if coolant had poured out of the cap. Had a look in and there was barely any coolant left in there. Checked oil - good level, no mayo anywhere and fairly new from the look and feel of it.
Started it up and pulled the oil breather pipe off - no noticable air movement. Had the coolant cap off and as it came up to temp, thermostat opened and the coolant began to bubble. As i revved the engine, the coolant would bubble more vigorusly. Also a fair bit of smoke/steam from the exhaust while revving. It still drives really well, plently of pull. Rad fan never comes on, despite the temp needle sky rocketting!

To me this clearly says headgasket, but any other possible causes before i give him the bad news? also anyone done a 1.4 HG? how much in parts and how long to do? difficult? does the head need to be fully stripped to be skimmed for these engines? (i've done the 1.2 8v HGs before.)
 
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its a bit early to confirm head gasket failure, it could also be water pump or a blockage or a rotten rad or even an extreme example of the very common oil circulation problem.

the fan issue is usually a rusty relay connection, the relay is on front of battery tray.

first thing to do is a compression test to decide if the head gasket has gone.

skimming the head means the cam and valves need to come out. if the cam lobes look worn (especially over cylinder1) then it is suffering from the oil circulation problem and you need to clean inside the oil bar (sits over cam) by bathing it in something like petrol or paraffin overnight.
 
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OK, tested and it isn't headgasket.

Tested thermostat while it was off, opening just before boiling point (sorry, didn't have a thermometer for a more accurate result :eek: but it DOES open.)

Radiators gone to be checked for blockages and/or leaks now.

Any other tests i should try?

EDIT: The cams appear to be ok btw.
 
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maybe it isnt overheating and the temp gauge is telling fibs. its common on bravos. a good thump above the needle can often fix it.
 
if the coolant is bubbling and pressurising the system, and there is steam in the exhaust, its time to get the torque wrench out.. you could do a CO test on the expansion tank to be sure though.
 
Right, well we removed the rad and had it checked... no blockages and no leaks. Although it didn't seem like HG, we removed the head and checked the gasket and surfaces - no sign of HG failure, new HG set and bolts were used to reassemble.

Still the same problem :bang:... when the engine comes up to temp, coolant floods out of the reservoir. Any ideas?
 
Just left it idling for 5 min... after 5 min, temp had just reached the red mark.

Fan never came on, but i think thats because the radiator wasn't actually that hot (and IIRC the sensor for the rad fan is on the rad.)

Top of the rad was a little warm (but that could have just been the exhaust manifold behind it) and the bottom of the rad was stone cold. Heater gave out no heat either.

Pipe to the top of the reservoir was roasting hot, pipe from the bottom was cold.

Any suggestions from these symptoms? its driving me nuts!
 
Had you not said you'd checked it... i'd swear it was a thermostat :confused:

Thats all I can think of. It did open in a boiling pan, but whether its opening too late may be the cause.

I didnt remove the water pump but checked that there was no play and that it span freely, which it did. How can i check that its actually pumping the coolant?

Pipes are deffo the right way round ;) they would only physically fit one way
 
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you said there was steam from the exhaust ?. Was this while driving with engine fully warmed up ?. If you're sure HG was OK, and the stat is opening in boiling water, the only other thing would be the water pump impeller spinning freely on the shaft, i.e not pumping at all. If the stat is opening then the rad should get warm as water circulates.
 
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you said there was steam from the exhaust ?. Was this while driving with engine fully warmed up ?. If you're sure HG was OK, and the stat is opening in boiling water, the only other thing would be the water pump impeller spinning freely on the shaft, i.e not pumping at all. If the stat is opening then the rad should get warm as water circulates.

To be honest, when i was running the car this afternoon, the exhaust seemed fine - that could have been because the car hadn't been run in a while when i first went to see the car.

I took the head and the old gasket to my local garage to ask for a second opinion from the mechanic who MOT's my cars etc, and he said from what he could see there was no evidance at all on either the head or the old gasket of gasket failure. The only thing that was a bit odd was that the valves on number 4 cylinder looked more sooty than the other three, but only slightly.

I can understand now why the waterpump could be a possible cause - i suppose if the coolant isnt being circulated, the coolant in the block is just going to get very hot and expand too much, hence causing the overpressurisation.

If the hose from the thermostat to the top of the reservior is getting so hot, that proves the thermostat must be opening, right? so i can rule out thermostat all together? therefore it must be waterpump?
 
i wonder if you caused an air lock when you put the blue stuff in. did you bleed all air out of the system by setting the internal ventiation to hot and then using the bleed screws with the engine running and up to temperature? first you use the rad bleed screw, then the one on the hose that goes to the heater matrix. you only close the screw when the bubbling stops. is that what you did?
 
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I bled it but not using that method - i pressurised the system with a hose in the top of the coolant reservoir with a rag and opened the bleed screw in turn until the bubbling stopped, but obviously this won't have opened the thermostat so air could still have been locked in the block, so i shall certainly give that a whirl (y)
 
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