Clementine's Garage
Clementine the Cat
 
Image of flower
Yellow R4
 
home my cars restoration tech tips guides forum
Réparateur d'automobiles

Overheating

D

Duncan

Enthusiast
Messages
9
Hi,

I am new to the forum. I recently bought a R4 1982 TL in France, its in general good order. I had a 20 km testdrive in 30c + tempretures and the engine ran very well, smooth and responsive. The next day when I collected the car and drove 50kms across country in very hot conditions and the engine again ran very well. on the next drive of about 40kms the temp light came on, I stopped the car and checked the water level and the fan belt, all was ok, I drove the car back home and the light stayed off. On the next drive the water started bubbling after about 50 kms. I am not familiar with the cooling system on the R4 motor, are there any weak points ? the Engine has done 150,000 kms and starts first turn of the key, there is no smoke from the exhaust and picks up very well, idling is bit rough when hot, grateful for any info on what might be causing the overheating. Also What manuals are available ?

Thanks for your time

Duncan
 
Welcome to the forum Duncan,

Do the TLs have an engine driven fan or an electric fan? One of the big failings of the cooling sytem on the GTLs is the electric fan switch on the side of the radiator which can stop working.

Another possible issue is air in the system. In the case of the GTL it needs to be filled from the radiator, and there is a bleed screw on the bulkhead near the heater pipe that needs to be opened until water starts coming out. This sounds the most likely cause of the problem.

The third possibility is the head gasket. You can check ths by topping up the system when cold, going for a run (30kms) then letting the car cool overnight. The next day if there is a hiss when you remove the expansion bottle tank then the water system has become pressurised, probably due to a head gasket failure.

The factory workshop is rare, but Haynes manuals come up from time to time on eBay, or cost £25 from Haynes.
 
Thanks Clementine,

The fan is belt driven, so I can discount that one - I dont think it is the head gasket as the oil is clean and does not have milky apearence that normally goes with a blown head gasket. I will give the bleed hose a go - do you have to have the engine runnning when you do this ? Unfortunetly I will not be seeing the car again until October. I also noticed that the top and bottom hoses where quite crusty, I have heard of hoses collapsing internally when they are old. The tempretures I was driving in were very hot and has obviously showed up a fault in the cooling system.

Many Thanks

Duncan
 
Funny you should mention collapsing hoses. The bottom hoses can sometimes go soft and collapse thus blocking off the supply of water to the engine. It's really difficult to diagnose, but I've only experienced it on a Peugeot 205 so I don't know if Renault 4s are prone to this.

Bleeding is best done with the engine off and the cooling system cold. Another trick that helps is to pump air bubbles out by squeezing the top hose. If the radiator is full, the top hose is full, and water comes out of the bleed screw then the system should be reasonably well blead.
 
You may need to rinse out the cooling system. Old cars collect a lot of goo in there. Use a garden hose and flush until the water that comes out is clean.
 
Its a typical R4 problem here in Australia even when the system looks in generally good order. I've also had problems with a GTL I bought in England and then went to the South of France- a previously trouble free car was lighting up and boiling on a daily basis- and flushing, flow checks, compression and leak checks were all done to check for a head gasket problem to no avail. It was great for my technical French though!

I suggest you try the following:
Thermostat- fit a hot weather one instead of the one it had in France, this opens at a lower temperature and they don't last forever anyway. Should be available locally.
Check there is no remains of a radiator blind or the cardboard blanking sheet fitted inside the grille.
Fit a 6-bladed plastic fan from an 845cc Renault 5- it is a straight swap, has the same diameter and much better performance. Renault still stock them and they are fairly cheap. If you are interested in this, I'll get the part number for you.
Have the radiator flushed out by a garage. In fact I strongly suggest having it recored or getting an exchange radiator. Flushing often doesn't really get all the rubbish out of the radiator passages. In the past I have had R4s where all the above plus previous suggestions have been done and only fitting a new or exchange radiator has finally cured it.
Hope this helps!
 
Duncan said:
The fan is belt driven, so I can discount that one - I dont think it is the head gasket as the oil is clean and does not have milky apearence that normally goes with a blown head gasketDuncan
Click to expand...

Head gaskets can fail in 2 areas. Between a water hole and an oilway (rare these days) causing milky oil - or between a water hole and the combustion chamber - most likely this is your problem.

Check that everything else is working (thermostat, bleed air out of system etc) and then start the engine from cold and remove the radiator cap. Look for bubbles of air coming up from the coolant. If this happens it will be the head gasket.

Steve
 
Clementine, if the cooling system remained presurised overnight would this not be an indication that the head gasget is ok as the pressure was maintained?

Ailbe
 
When the engine is completely cold, unscrew the coolant filler cap and then screw it back again. Then immediately unscrew it again. There will be no hiss. The system should be at atmospheric pressure.

Go for a good drive, then let the car cool overnight. Next day try unscrewing the cap. If there is a hiss then there must be more gas in there than you started with. It has to come from somewhere. That somewhere tends to be the high pressure combustion thing going on in the cylinders that's leaked past the head gasket.

OK so this won't work if the start and finish points are at different altitudes, but that's what I was getting at.
 
right I think a few of us don't fully understand cooling systems.

Its a sealed system (or meant to be) the system builds up pressure thats how it cools. The cap on there will be in the region of 1 BAR rated.

The cap will allow the system pressure outside the engine (engine pressure is higher) to reach a maximum of 1 bar before venting.

The caps a decvice with 2 springs, 1 pressure 1 vacuum. The pressure sppring is what dictates the venting pressure.

The vacuum spring allows another valve to be drawn down to let air into the system. if you have a car with a coolant leak that leaks a good amout the cap will be hissing all the time as the airs going in the coolants going out.

The vacuum spring is really for atmospheric changes and gradual pressure release. When the cars run the pressure should build up in the system. The pressure should be maintained in the system overnight at least. A really good system will hold pressure for a few days.

Another issue is these cars are pretty old, they also use hoses that are braded on the outside in some areas, the rubbe rinside collapses and causes an intermittant blockage thus you get issues.

40 year old rubber is never going to be as supple as new stuff so it can just break as well.

To discount a headgasket leak get down an MOt station and get them to put the emmision tester int eh header tank, not in the coolant though just in the tank, if theres any trace of HC's then the gaskets gone.

Radiator, again 20 odd year old radiator is a bit passed it and it will be silted up. Flushing may help as long as the radiator is in fine fettle (not missing half its fins etc) then give it a good flushign and see what happens. If its damaged then recored or new unit is the best option.

Last but not least check the sender for the light. On 1 of my 19 16V's when the gauge read temp as normal the light came on (they operated off the same sneder btw) but when the fan kicked in the light went off. Another sender problem solved.
 
Duncan, when you bleed your cooling system don't forget to unclip your expansion bootle and lift it higher than the bleed pipe! Close the bleed screw before replacing it!
 
You must log in or register to reply here.
Community platform by XenForo® © 2010-2024 XenForo Ltd.
Back
Top