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

High Tickover

D

DaveP

Enthusiast
Messages
147
Had to replace fuel pump on my TL and I'm worried a little fuel may have contaminated the oil, the car is running well when cool but tends to overheat when being driven for a few minutes above 90 kmh, I say overheat, the light comes on but it seems to soldier on happily enough. The hotter it gets the faster tickover becomes so I'm guessing an oilchange would possibly cure it but the oil doesn't smell of petrol. I've drained and refilled the rad and bled it (I presume the hose hanging out of the bulkhead is the bleed valve) which hasn't really helped. It's 30 degrees plus every day at the moment here so it's a bit of a worry. Any other thoughts?

As an aside the hot/cold switch slips so I can't put the heater on to blow the excess heat out. I'm going to pull it apart tomorrow but I thought someone might have some handy hints.

Cheers all
 
Heat causing high tickover could well be petrol in the oil (comes in through the breather). Well worth changing the oil.

Which TL do you have? If it's the later one with electric engine cooling fan it might be worth checking that the fan is coming on when it gets hot. Could be the thermostat is sticking - the radiator should be hot to the touch as soon as the thermostat opens (5 minutes running maybe).

For bleeding the radiator the expansion bottle should be removed from it's mounts and placed on top of the wing. Squeeze the top hose until tle air has been removed (and drain from the heater).

And check the oil level - it uses the same light as the temperature sensor.
 
Oil level is fine, I have an oil pressure light too, the car is an 84 tl lhd. It's very frustrating as it goes really well and would cruise happily at 120kmh but for the overheating, when I throttle back it cools, but only at lower speeds, say 60kmh, surely the higher speed should be ramming more air through the rad? I'll check the fan as you suggest, I think it's electric. Is there a thermostat which cuts in at a lower temp available? Is it possible the main jet is running lean? I can't find any adjustment for this.

Finally, with the ambient temperatures here, would I be sensible to put 20w 50 oil in rather than thinner stuff, at least until it cools down?
 
I have the belt operated fan. Changed oil and filters, car runs really well, will happily sit at speed but the overheat light comes on, maybe it's just lying? The only other thing I can think is either the waterpump is weak/broken, which seems unlikely as it's fine at lower speeds or the car simply doesn't have enough cooling capacity for the hot weather.There's so many tl's around here though that can't be true, can it?
 
Usually, when the "trop tard" light comes on, the coolant can be felt to boil in the expansion tank. It is made to light at 112 deg. C, so if it comes on and all seem fine when you open the bonnet, it could well be a defective temperature sender. Remove it (left hand side of water pump, connect a multimeter to it (one lead to the sender itself, the other to the terminal and place it in boiling water, the multimeter should still indicate open circuit. If you find a thermometer capable of reading that high, you can do the above test with oil so that you can reach the 112 deg. C temperature and check what happens.

Assuming that it actually overheats, is your radiator OK? It may well be clogged inside.

Also, the water pump that you mentioned can be a source of trouble, I had a 1108 recently that ran hotter than normal and eventually overheated, while all the cooling circuit appeared fine. I noticed, finally, a tiny leak from the water pump, so small it could be taken for normal, I replaced the pump and it ran at least 15 deg. C cooler...
 
Definitely worth checking the warning temperature sensor. It was faulty on our R4, but we didn't realise after spending a long time bleeding the cooling system, after having replaced the radiator.
Good luck!
 
I've checked and it definitely IS overheating, I flushed the rad a week or 2 ago via the drain hole, might give it a go taking the hoses off. How does one flush the heater matrix? There seems to be a hose running into the bulkhead high up.
 
Decided today that it HAD to be the thermostat, so when I got the car home I went to take it out, it's already been removed. I can only assume the car had a fault for a while which someone has tried to "cure." The heater is blowing out really hot (hurts my feet) air so there's obviously no blockage. The problem has got worse, driving normally in ambient temps of 23 degrees today it overheated (ie light on) inside 10 kms with heater on full. It seems the heater is the only cooling though, as soon as I turn it off the car overheats. Short of a new rad I'm stumped. I've stripped all the hoses off and they're slightly rust lined but not blocked. Surely if the water pump was broken the heater wouldn't work? Any help would be greatly appreciated.
 
Have you thought that it could be the head gasket? Are you losing water out of the overflow? Can you see bubbles in the water when removing the resevoir cap?
 
Doesn't seem to lose any water, except when boiling over, would bubbles be there when it's cold or only when hot? By reservoir cap, do you mean the radiator top or the bottle? The car seems to run far too well for it to be head gasket, though the thought had occured to me. The fact that it's getting worse despite everything I do seems to point to it I suppose. How tricky is a gasket change?
 
Easy way to check. With the engine cold remove the rad cap and top up the water. Replace cap. Fill the resevoir up to the top and leave the cap off. Start up the engine and if the head gasket has gone you will see the compression gases pushing the water out and lots of bubbles. If this happens, smell the gas from the bubbles - it will smell quite distinctive.

If the head gasket need replacing please search this forum as there are plenty of tips. I would also suggest you buy a manual.
 
Hi Dave, I had mine done recently at a local (French) garage and they took out the block and sent it away to be skimmed and tested. And fitted new water pump, thermostat, plugs, etc. About 600 euros altogether but well worth it to get a 'new' car back.
 
A way to double check for head gasket problems is to fill the car when cold, drive for 10 miles, then leave it overnight to cool. Then remove the expansion bottle top - if there's a hiss then head gasket is likely. They do tend to blow head gaskets if allowed to overheat.

Causes of overheating might include blocked radiator, soft or linked lower hose which closes when it gets hot, poorly bled coolant system (normally reasonably self bleeding so long as you fill from the radiator).
 
Followed all your advice for checking head gasket failure and it seems ok, so I decided to pull everything apart for a look, took all hoses off and removed water pump, it was all slightly dirty but not terminally so, found nothing so put it back together. Bled the system really really well and ran it for a while, seems to have improved greatly, still gets hot if I thrash the car, but runs ok for sensible speeds (up to 100kmh) so considering it's 30 odd degrees here I'm happy enough. I may try some anti kettling additive to bring temps down further.

Is there any reason I can't run a bit of vinegar through the rad to clear scale? I did it on an old ford kent engine and it worked rather well.

Thanks for all the help, this is an incredibly useful site
 
Ps Blue bell, I'd love to get the engine rebuilt, but 600 euros is double what I paid for the old girl, might be a treat for her in a year or two if she behaves. Did you get hardened valve seats put in at the same time?
 
To clear the scale then I suggest buying some 'radflush' or similar. If the scale is very thick then use Fernox DS3 descaler - this is what plumbers use and it's very heavy duty so you don't want to leave it in your system for very long. I'm a great fan of this stuff and have had good results. Look at it this way, in the home I have kept the same shower head for the last 10 years, it descales a kettle and the filter in minutes and cleans up the loo pan nicely!!!!
 
DaveP said:
Ps Blue bell, I'd love to get the engine rebuilt, but 600 euros is double what I paid for the old girl, might be a treat for her in a year or two if she behaves. Did you get hardened valve seats put in at the same time?
Click to expand...


600 euros is cheap for a full engine rebuild on the R4...bear in mind that pistons/liners cost at least 200 euros and any engine with wet liners is time-consuming to be assembled properly (=high labour cost).
 
Angel, I think that Bluebell meant the cylinder head rather than the block. I read it as a top end overhaul.
Bluebell, correct me if I'm wrong!
 
Yes you must be correct...in which case is a bit pricey by our standards.
 
Sorry to be misleading but they did send off the whole block to get it tested. No new liners though. Seven and a half hours work plus transport costs.

Quite happy to pay 600 euros as we can't do it ourselves and we can't even get the car off the road at the moment, the garage being full of boxes and furniture. Mr B is also busy building a swimming pool!! :)
 
You must log in or register to reply here.
Community platform by XenForo® © 2010-2024 XenForo Ltd.
Back
Top