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Over Heating Continues - Any Help?

The4seeker

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The Renault still overheats I am well puzzled?? Please bear with this long post

1/ If I start up the R4 and let it just run in the garage it runs up to temperature and the fan comes on and off. You can leave it for a couple of hours - no problems.

2/ Whem driven the red light comes on within a mile, and is bubbling water from the radiator cap and the expansion bottle!!!

3/ I live on a steep hill it produces the same results from starting from cold and reversing up the hill say 20 feet!!!The water is still cold!! and is bubbling like point 2!!

4/The water system seems to take on a massive amount of air, but only when driven and under load, if I bleed it and don't drive it it never overheats

Any ideas wecome...car has had the following work to cure the problem in no particular order.....and in fact having now done all this ITS WORSE than ever could drive 5 - 10 miles now only 1/2!!!

NEW RADIATOR
NEW HOSES
NEW THERMOSTAT
NEW WATERPUMP
NEW HEAD GASKET AND CYLINDER HEAD


help me please
 
If it overheats in 20 feet use it must be one of two things - either the system has a lot of air in it, or the head gasket has failed so the system gets a lot of air in it.

If you are sure you've bled the system correctly (procedure is in the Haynes manual, and they self bleed quite well so long as you get the bleeding close) then it's most likely the head gasket. I've only got a 1 in 2 success rate for head gasket replacement in wet liner engines, so It wouldn't be surprising for a new head gasket to leak.

It's reasonably common for the head gasket to fail is the car has previously been overheated, and it would explain the air getting in under load. The air pushes the water out which makes the engine hot and pushes the rest of the water out.

Options would be a replacement engine (for £50 or so) or changing the gasket. It's not a lot of work to change the gasket, but I'd personally recommend changing the paper seals at the bottom of the wet liners at the same time. Theoretically it's possible to replace the head gasket without moving those seals by not turning the engine over while the head gasket is off, and clamping down the liners, but I've never managed to do it.

Might be worth an engine if you can find one. I've got one you could have for nothing, but a valve needs to be replaced, and that would involve pulling the head off. Someone else will surely have an engine.
 
Got to disagree with you Malcolm. I have replaced more head gaskets than I can remember including Renault ones. I have never had one fail on me because I always have the head skimmed, especially if they are aluminium. On engines with wet liners I always have managed to clamp down the liners so I can bring the pistons to the top for decoking. One of the key things I do is to thoroughly blow out all the crap from the bolt holes in the block and I even run a tap down them if necessary. I also clean up the bolt threads as well. This is to ensure that when I torque the head down it is a true reading and I'm not torquing down on oil, water or crud accumulated in the bottom of the bolt hole. If the paper liner seals are not letting water in the sump then I leave well alone.

With this 'problematic' engine it may just be a case of poor assembly procedure.
 
Actually I had a thinking moment half way through that post. Problems with those paper seals wouldn't cause pressurisation problems. Only water leaking into oil problems (which I didn't have).

It's possible I messed up in other ways with my previous attempt.
 
I would have to agree with Steve
Almost every 4 and Phase 1 R5 I have has had a a blown head gasket at some time One so bad that the exhaust was coming out of the expansion bottle cap Provided you break the seal by leaving one head bolt in no 1
I think in the haynes picture Then break the seal sideways the heads come off leaving the wet liners in place You dont need to turn the engine over with the head off for a gasket change Only when the head is back on you need to turn the engine to set the valve clearances The only problem I have found is getting out 2 head bolts in the middle It states in the manual you need a special Renault 14mm socket But you can get round that by turning the valve 90 degress with the push rod removed and pushing the rocker one way or the other
I have done about 15 head gaskets now on Renaults and have got it down to 3-4 hours
Another thing I have noticed is that the rocker cover seens to fill with condensation even after chaging a head gasket That makes you think the gasket has gone again
 
overheating

Thanks everybody for your help.

Liam - I will have the head crack tested when I remove it this weekend
 
Compression Test

Strangely all four cylinders read 175 psi on a compression test, so I am a little reluctant at this stage to take the head off.

Or could it still be the head???
 
Does seem a little high for something with a serious head gasket failure. You might try one last attempt at bleeding. My technique (with the engine cold) is:

1/ Turn the interior heater to hot.
2/ fill the radiator directly from the top of the radiator (remove the cap that says do not remove). Put the top back on.
3/ Fill the expansion bottle and leave the top off.
4/ Undo the straps on the expansion bottle and get someone to hold it higher than the engine.
5/ Undo the plug at the end of the little pipe coming out of the bulkhead from the heater and wait for a stream of water without bubbles to come out before screwing the plug back in.
6/ Using both hands squeeze the top hose to the radiator. Air will bubble through the expansion bottle. Keep doing that until the top hose feels like it is full of water.
7/ Re-check the level of water in the radiator. Should be full to the cap.

Put everything back together, top up the expansion bottle, and start the engine. Let it idle until the radiator and top hose get hot (thermostat opens). Any remaining bubbles should bleed out through the expansion bottle during running. Make sure the heater is still on.

When the engine has cooled sufficiently top up the expansion bottle to the correct level.

The final trick. If you take the car for a short run, then leave it to cool down completely (overnight), then open the expansion bottle cap and hear a hiss, then chances are the head gasket has failed. Any hiss would be due to pressure that has appeared in the system that wasn't there last time the engine was stone cold, and the only place it can have come from is a leaky head gasket.
 
Wet Liners

If the wet liners are leaking water into the sump could this cause the overheating, I have have the head of now and it wasn't that.
This air in the water has too come from somewhere.


PS When I take the expansion bottle cap off over night it bubbles crazy !!
 
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