Mysterious Coolant Loss... Part Deux,

Following on from the previous thread, I've just bought a '98 C2 Tip. On the way home from the sale, 2 litres of coolant simply disappeared. No sign of leaks, drips, white marks, tho there was a faint smell of coolant from the engine area. Word back from the garage today is that they pressurised the system and cannot find a leak. I've asked them to take the PU off and inspect the rads, clear debris etc, which they've done. They tell me the rads have recently been replaced. Any thoughts? Was the system just not pressurised enough? Could it be that there has been air trapped in the system waiting to bubble up when the car got a good work out? (Spirited drive followed by 30 mins in stop start traffic) Any other ideas? Thanks! PS , some pics are due I suppose... very happy with how she has weathered her years, no rust to speak of, a little surface only on the radiator brackets, this being sorted and protected.

If the rads had been replaced in say the last 20 miles then an airlock is possible .. if we are talking a couple of hundred then no . car at temp .. a/c on so the fans are running .. smell the air flow from each rad .. a sweetish smell indicates a slow rad leak . No external leaks so its just about possible its internal .. to the car that is .. any sweetish smell inside the car .. carpets damp in the front footwell either side .. heater matrix is what i was thinking .. long shot though . Rad cap is blue .. any white crusty stains on the edge .. this would indicate a new cap is needed . Last would be the coolant tank is split .. normally along the seams ... For now its a case of drive it and keep an eye on it .. if its got a leak then you will be topping it up again .. if not ... Happy days ! Edit .. You need new from discs judgeing by that lip

^^^^^ Eagle eye! They look like secondhand rads? Looks like the number 130 is written on one?

I'll take your old ones off you for a small fee :grin:

Thanks again y'all! Great to get professional advice from you DeMort, very much appreciated. For info, new discs pads sensors were dropped to them today. Yes the rads are new but not that new, but it's not really been used at all in the last two years A couple of hundred miles at most, and then it's been only a few miles every 3-4 weekends. The fans are working on low with ac on. No smell of coolant up front or in cabin but there is a smell of same in the area of the header tank. However the pressure check showed no leaks! Could the leak need higher pressure?! Also, no sign of white staining on cap but it's a .00 so there's a new one on the way, with a low temp thermo for good measure. The engine compartment fan was recently changed. I'll take your advice DM and run her , with a gallon of coolant mix sitting behind me! Thanks again. I'll keep the thread updated.

If your useing a pressure tester then it will have the green to red colours on it .. dont go very far into the red as you are going beyond what the car will do . I think its about 20 psi on our tester .. a little into the red basically and thats as far as i go . Coolant tank splits along the seams but should show up on a pressure test .. not a leak ( depending on coolant lvl ) but a loss of pressure when left for 20 mins on the tester . For now you just need to do a few miles to see if its actually got a leak i feel .

Thank you very much for that valuable advice DM, I'm hoping to get the car back tomorrow, I'll put it thru it's paces and report back. I may be wrong but the problem with the tester is it doesn't reproduce the situation where the hot coolant expands pipes and joins. Having read a few more of your posts, I'm going to prioritise waxing the car underneath, so thanks for that pointer too. Rgds Barney.

watching this thread with great interest, I'm having exactly the same problem. Using about a cup full of water every 200 miles and no idea where it's going.

I have similar problem, my leak is on aluminium pipe where joints with rubber pipe very small usually is nothing on floor as when you driving air is pushing away all drops, you will have to check under car all connections, also I have read about GT3 problems with pipes popping out from engine I don't know if this is an issue in standard models so advise from expert like deMort more then welcome. Mine was easy to find as white shite build up around it.

Thanks again! I have the boys at the garage going over the coolant pipes this morning with particular attention to the crossovers. If they're in good condition they are going to get a lovely coat of wax. Will report back once I've the car back and a few miles put under her.

The way i test with the car hot is a bit iffy so i dont really want to explain it .. so ill say this .. If you run the car upto operateing temp from cold .. the system will have as much pressure in it as its ever going to have .. so you are in effect pressure testing it just by running it up. 996 dont have crossover pipes as such like the 997 but theres plenty of pipes for them to look at lol . Your problem is you cant see all the pipes due to the undertrays .. im guessing anything obvious will be found when its inspected .. today i think

That fault wont happen on a 996 C2/4 . White Shite .. thats what I look for 997 and its Pink / White shite :floor:

Well I don't think the news is all that great .. All was wrapped up with the car this evening. I went over to pick it up. The garage had brought it up to temperature and then sat it running as a last test. All good, until it suddenly spewed the guts of s litre of coolant out thru the coolant cap. The dash temp was at about 100 degrees st this stage. Half way between the two dashes. I'm hoping it just hasn't been 'burped' properly, but it still doesn't explain the first loss of coolant. Pissed off and getting stuck into a bottle of Gordon's. This is no way to start back into 996's. :grin:

Did you have the coolant cap set to let out the air, it shouldn't really let out coolant.

I'm not sure what's going on with that cap but there is a replacement on the way. I'd like to think it could be that simple .. but ...