Overheat and coolant problem

My wife was driving our C3 home the other night and the overheat light came on. She got home and the fan kept running for 30 mins after she stopped the car. After it cooled down I checked the coolant and the level was very low. I topped up with new coolant, and the car drives fine, but the pink coolant is turning black and seems to needing topped up again.

What are the likely causes of these symptoms?

mitchino wrote:My wife was driving our C3 home the other night and the overheat light came on. She got home and the fan kept running for 30 mins after she stopped the car. After it cooled down I checked the coolant and the level was very low. I topped up with new coolant, and the car drives fine, but the pink coolant is turning black and seems to needing topped up again.

What are the likely causes of these symptoms?

Hi mitchino, two problems, one you have a small coolant leak, probably only a pin prick size hole in a hose or something similar.

and the other problem could be due to mixing two chemically different antifreeze solutions. One was already in the car, the other you added.


Have a look for the leak (with caution if the engine is hot), when you replace the faulty part, drain the system completely, flush it out and refill with the pink OAT stuff.

There are some pictures of the cooling system pipes and drain point in this topic

Thanks for quick reply - spoke to local mechanic, he thinks it's blown head gasket. There does seem to be some oily black stuff in the coolant. No sign of water in the oil though. He says I should just get rid of the car (done 60,000 miles). His garage doesn't do head gaskets. He also says should be ok to keep driving it on short journeys.

What do you think next step should be?

mitchino wrote:Thanks for quick reply - spoke to local mechanic, he thinks it's blown head gasket. There does seem to be some oily black stuff in the coolant. No sign of water in the oil though. He says I should just get rid of the car (done 60,000 miles). His garage doesn't do head gaskets. He also says should be ok to keep driving it on short journeys.

What do you think next step should be?

That's up to you. It depends if you want to spend money on it because you like the car and know its history or you can afford to loose money on it and take a gamble on a different car.


If you remove the oil filler cap, is there any mayonnaise - indication of water in the oil.

There are tests for combustion gasses in the cooling system to confirm the diagnosis of head gasket before making expensive decisions. The video below shows a system.

You can find the stuff in the video here - head gasket test kit, it is a cheap way to test for combustion gasses in the coolant.

mitchino wrote:He also says should be ok to keep driving it on short journeys.

These things never get better, only worse, and sometimes its a very rapid decline. If it were me, I wouldn't risk breaking down with a blown engine, for me, its just too much hassle. I wouldn't drive it or get I would get it fixed, one of the two, but never ignore it.

You are always free to get a second opinion from another mechanic. It is much easier to diagnose problems and make decisions when the car is right in front of you.

There is no coolant in the oil as far as I can see. No mayo. But if I stick my finger in the coolant reservoir, and run my finger over the inside, it picks up dark oily deposits. The car is running fine, drove it for 2 hours today, no loss of coolant, didn't overheat. If it is the head gasket, how much should I expect to pay for a repair? Google suggests £250-400. If that is right then it's worth repairing. Finally, what about steelseal, kseal and other products? Are any of them any use?

mitchino wrote:There is no coolant in the oil as far as I can see. No mayo. But if I stick my finger in the coolant reservoir, and run my finger over the inside, it picks up dark oily deposits. The car is running fine, drove it for 2 hours today, no loss of coolant, didn't overheat. If it is the head gasket, how much should I expect to pay for a repair? Google suggests £250-400. If that is right then it's worth repairing. Finally, what about steelseal, kseal and other products? Are any of them any use?

I don't know how much you would pay someone else to do a head gasket, I have only done them myself so it only parts I had to pay for. A few calls to local mechanics would give you a consensus of opinion for prices. The time is the real cost as the head gasket itself. The cost of the gasket is costs only £15 or so and you can pay more if you get more gasket parts in a 'kit'. Like these ones (click here) that include a timing belt and head bolts, all worth considering a change while the head is off.

The C3 full monty head overhaul set.



I have never used the products you mention, I suppose if they are cheap it could be worth a try?

What have you got to loose?

It would be worth getting a confirmation that it is the head gasket before getting work done that may be unnecessary, similar to the video or something along those lines. It would be unusual for the head gasket to fail at 60K, so there may also be problems that caused the gasket to fail, or some other fault is giving you oily stuff in the coolant.

Just took the car down to my local mechanic, the one who "doesn't do head gaskets". He had a feel in the coolant reservoir and agreed there is some oily stuff in there. He then held a gas analyzer above the coolant and revved the engine, and found that no combustion gases seemed to be coming through the coolant. His opinion? Flush out the system and then keep an eye on it to see if oil starts to come through again. I asked him about Steelseal etc, and he said he's never used them, but was of the opinion that it might be worth a try. He wants us to check if the timing belt has been changed, I couldn't remember but the car has done 64,000 miles so I suppose it should have?

My brother says get rid of it - flush the system, refill with fresh coolant and stick it in an auction. Slightly dodgy!

Citroen say somewhere along the lines of 80K/10years for a petrol cambelt, but sooner is better than later and haynes says 40K if its used for mainly short journeys.
10 years is a maximum.

mitchino wrote: My brother says get rid of it - flush the system, refill with fresh coolant and stick it in an auction.

He may well have a point

So I've decided to try Steel Seal to fix my possible head gasket leak, been advised by mechanic that I have nothing to lose by trying it. The car has been running fine for last two weeks, no overheating.

So I've removed bottom radiator hose and flushed through from expansion tank, and then flushed backwards from bottom of radiator. Also tried to flush through top radiator hose.

How can I flush the engine waterways or does that not matter?

I noticed when I pulled the bottom radiator hose that the coolant was green, so maybe it is just a two types of coolant mixed problem?

mitchino wrote:How can I flush the engine waterways or does that not matter?

To get to the engine waterways you need to get to the thermostat. If you remove the thermostat you will have access to the engine waterways.

mitchino wrote:I noticed when I pulled the bottom radiator hose that the coolant was green, so maybe it is just a two types of coolant mixed problem?

Flushing the whole system sounds like a very good idea. If you are unsure of what is in there a full flush and refill of the correct stuff has to be the cleverest option.