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Overheating At Idle!

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#1 WimpyMiniMan

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Posted 24 January 2016 - 05:27 PM

I had an engine overheating problem where basically the engine would start steaming after minor use. So I replaced the radiator, rad cap and top and bottom hose, along with the thermostat , however I've been running the engine at idle to test the new system and although I see no leaks, coolant seems to be bubbling out of the overflow pipe. I'm pretty sure the coolant level is right - and the radiator gets very hot and rumbles like a kettle. Also the engine temperature gauge in the car reads above normal but is not in the red (however I don't think driving the car at this stage is a good idea). I suspect there could be a blockage in the water jacket and/or the water pump may not be working... what do people think? 

 

Kind Regards

George



#2 CityEPete

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Posted 24 January 2016 - 05:29 PM

Water pump sounds favourite to me but I am sure more knowledgable folks will be along shortly to help :)

 

What is the heater doing? Could be an airlock?


Edited by CityEPete, 24 January 2016 - 05:30 PM.


#3 WimpyMiniMan

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Posted 24 January 2016 - 05:30 PM

the heater wasn't blowing any air though when i turned it on.



#4 Spider

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Posted 24 January 2016 - 05:52 PM

Head Gasket?



#5 WimpyMiniMan

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Posted 24 January 2016 - 05:56 PM

I see no leaks on the head gasket and the engine does not sound like it's misfiring. What do you mean? I just seems to overflow and bubble out of the radiator overflow pipe, and the radiator itself gets very hot.



#6 cal844

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Posted 24 January 2016 - 06:05 PM

Sounds like a blockage somewhere (heater is my favourite) or a big air lock

#7 ukcooper

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Posted 24 January 2016 - 06:08 PM

Head gastket genaly give no sings of leaks or misfires you need a compression tester to see if there is a general problem.

 

Steam could be from the water pump as there a little hole on the underside of the pump

 

Water pump could of failed.

 

Wrong rad cap.

 

Air lock.

 

Heater full of crap and wants flushing. you should have the heater on hot and the fan on when bleeding the system.

 

Block or heads cracked.

 

Timing out.

 

Car getting to hot as it idling to much.



#8 Spider

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Posted 24 January 2016 - 06:18 PM

I see no leaks on the head gasket and the engine does not sound like it's misfiring. What do you mean? I just seems to overflow and bubble out of the radiator overflow pipe, and the radiator itself gets very hot.

 

The Head gasket can fail in many ways or put another way, via many paths. In this case - and this is by no means certain - from the Combustion space to the cooling jacket, that would cause the coolant to heat up pretty quick along with bubbling (which could be combustion gases if it's head gasket) in the coolant.



#9 WimpyMiniMan

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Posted 24 January 2016 - 06:27 PM

I think the steam is coming from the boiling coolant which pools below the rad on the sub frame, as it only steams a lot when the car is turned of and therefore the rad fan is not blowing the steam away anymore. I have just refilled the coolant so there could be an air lock - I will run with rad cap off and heater on until warm. The rad cap is the 15lbs one as advised by the haynes manual and the thermostat is the standard 88 degree celsius and is brand new. The rad seems to go from not hot at all to boiling very quickly however I presume this is as the thermostat is allowing the coolant out of the block. I dont know whether the water pump is working - what is a good way of checking? The heater does work but doesn't get hot very quickly which makes me think this could be a problem, and also the car worked fine before until it started overheating, which makes me think it is probably not an air lock as between it working and not working the coolant was not changed. I dont know how to change the timing - i presume this is most likely a specialist job. The car was idling for about 10 mins but i dont think this is just idling too much.

 

Regards

George



#10 Cooperman

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Posted 24 January 2016 - 06:28 PM

Ignition timing too far retarded?



#11 WimpyMiniMan

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Posted 24 January 2016 - 06:39 PM

Ignition timing too far retarded?

What does this mean? 



#12 Cooperman

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Posted 24 January 2016 - 06:58 PM

Sorry, we tend to assume that classic car owners are 'into' the mechanics and electrics of their classic cars (if not, then they need to be rich ;D ).

The ignition timing is the point at which the spark happens as the piston travels up the cylinder bore on the compression stroke. The spark happens slightly before the piston is at the top of its stroke (known as Top Dead Centre or TDC). Normally the engine is timed statically at between 6 degrees and 8 degrees of crankshaft position before TDC and as the revs increase the spark timing happens earlier so that at high revs it is somewhere like 32 degrees before TDC.

If the spark happens later than it should, the timing is said to be retarded. An engine with retarded ignition will run hotter. In extremis it can make the exhaust manifold glow dull red and cause the coolant temperature to be too high.

You can re-set it yourself statically, but it can be the distributor itself not advancing properly for one of a couple of reasons. If it's a points-type distributor it can be sticky bob-weights in the bottom of the distributor which control the rate of advance centrifugally, or by a failure of the vacuum advance control pipe.

I hope I'm not getting too technical here.



#13 WimpyMiniMan

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Posted 24 January 2016 - 07:07 PM

Sorry, we tend to assume that classic car owners are 'into' the mechanics and electrics of their classic cars (if not, then they need to be rich ;D ).
The ignition timing is the point at which the spark happens as the piston travels up the cylinder bore on the compression stroke. The spark happens slightly before the piston is at the top of its stroke (known as Top Dead Centre or TDC). Normally the engine is timed statically at between 6 degrees and 8 degrees of crankshaft position before TDC and as the revs increase the spark timing happens earlier so that at high revs it is somewhere like 32 degrees before TDC.
If the spark happens later than it should, the timing is said to be retarded. An engine with retarded ignition will run hotter. In extremis it can make the exhaust manifold glow dull red and cause the coolant temperature to be too high.
You can re-set it yourself statically, but it can be the distributor itself not advancing properly for one of a couple of reasons. If it's a points-type distributor it can be sticky bob-weights in the bottom of the distributor which control the rate of advance centrifugally, or by a failure of the vacuum advance control pipe.
I hope I'm not getting too technical here.


I'm very interested in the mechanics and electrics. - I bought the car as a project - however I'm new to it so will be a steep learning curve :) just learnt all about tapping :) thanks for the explanation and I will read up on it and have a fiddle.

Regards
George

#14 mingy

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Posted 24 January 2016 - 07:09 PM

You have stated the heater does not get hot very quickly, even when the coolant is well above the normal temperature. This sounds to me as though the water pump has failed,  I would drain the system completely and take the water pump off and check that first of all, they are not expensive and a new uprated one would probably benefit the cooling system. If that solves the problem i would also check the flow through the heater matrix by removing the the hoses from the heater matrix and       ( this is how i cleaned mine out ), then i connected a garden hose pipe with a jubilee clip to one of the heater tubes and another short length ( enough to exit the car door ) of garden hose pipe to the other heater tube and allow a slow flow of mains cold water through the heater until you can see a clean clear flow of water, i then allowed more mains pressure to flow through the heater until i was happy with the flow.

I would also check your radiator after this but, i am sure that will be ok.  



#15 CityEPete

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Posted 24 January 2016 - 07:48 PM

Don't put mains pressure water through the heater matrix! It will burst it especially if it's getting on a bit.





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