Last week my car said I was low on coolant, I added maybe 8oz tops. At the time I didn't notice any leaks, the car was parked for a quite a while before I put in the coolant. About two days later I notice the smell of coolant popped the hoof but still can't find any leaks or sign of a leak. I parked the car over a large piece of card board that night and still no sign of a leak on the clean cardboard. I pressure tested the system today and still no sign of a leak. The engine is pretty tight no leaks anywhere so it's clean. Drove the car a few miles and noticed the smell of coolant again. Stopped and popped the hood and I noticed a tiny little puff of steam right at the crankshaft pulley but no sign of a leak and I am not sure it was from the coolant. The water pump Timing chains and guides were replaced a little while before I bought the car and the work and parts are only about two years old. I had two people look at it and both can't find a leak I was told it could be the thermostat housing or some O ring. So far the coolant level is still where it was when I put some in last week. A firend of mine who works as a mechanic at a Mercedes dealer ship suggests I put in stop leak. He claims they did it a lot at all three places he worked. I am not a fan of stuff like this and do not want to put anything in the cooling system that might clog the system. Any suggestions of tracking this problem down. I have no problem doing some work on the car if it needs it just do not want to pay too much for someone to start replacing items I do not need.

Thanks in advance!

 

I think you said that the reservoir was down 8 oz after 2 years. That's not much and some of that could have been just less than perfectly full after the water pump replacement.

The pressure test you mentioned is your best hope of finding a leak. Try that again and pump it up to 20 lbs and leave it awhile. You obviously have a very small leak.

I agree with you on the stop leak, I wouldn't do it.

 

He ain't no "mechanic" in my book.
Vector

 

Stop-leak is a last resort, not the first.

 

Thanks guys, I am going to do another pressure test on it again and see if I can figure it out. As far as the Stop Leak goes it would be the last resort even though I talked to two other mechanics and they also suggested it as well. One guy who has been a GM mechanic for over 30 years said they put a sealant in cars right out of the factory and it's one of the reasons if you don't get the car serviced when it calls for a flush and change the coolant the heater cores clog in the newer cars with aluminum engines and or heads. The other guy claims every time his shop changes a head gasket they put a sealer in the coolant. I never used it when I was doing mechanics because it just looked like mud I would imagine the stuff they use today is probably better but I just do not trust it. So far the car runs at the correct temp and loosing 8 oz in two years wouldn't be bad but I think I lost the 8 oz in the last few weeks it looked good last time I checked a few weeks ago when I changed the plugs and checked all the fluids and levels. These days with so much plastic on and in engines it surprises me there are not more problems.

 

Actually, the plastic parts can cause problems after a while anyway. The thermostat housing can weep - I replaced mine with an aluminum after market part. The output pipe on the front of the engine can also cause problems - one end of mine got a bit out of round and I had to replace it. They only come in plastic though, as far as I know. The plastic vanes in the water pump can also disintegrate - there's been a lot written about this and the different evolution of materials used.

 

I had a Merc Sable I was given a few years ago that was in mint condition low miles but the heat didn't work. Turned out the plastic impeller in the water pump disintegrated clogging the heater core. I pulled the pump and the whole housing was trashed and also had to be replaced luckily I got a NOS one on Ebay for $20.00 with a metal impeller and housing attached. I never bothered replacing the heater core there was only one day that winter I wished I had heat. I am trying to find out what type of water pump was put in when it was replaced a couple years ago. As far as the other plastic parts go I will replace those as well if they haven't been changed yet. Luckily I have a wholesale account with a part supplier so parts are cheap for me. It's the labor that can get expensive a I worked on cars for year and these day I just hate doing the work myself. My mechanic I uses is very reasonable so if the pump and housing needs replacing he will get the work. Now I had the car checked again yesterday and they say they can't find a sign of a leak anywhere but everyone agrees they smell coolant. I guess I'll drive carefully keep an eye on the temp and look for signs of a leak. I also checked the fluid level and it looks like it hasn't gone down at all.

As far as plastic goes I don't mind plastic parts but think they should not be used internally in any engine at all or used for the cooling system.

 

I have the same issue.. In my case, there is a slight weeping at the front of the engine, behind the pully.. Enough to show on the block, but not enough to leave any puddle or drip on the pavement..The smell is very annoying, but my levels seem to stay steady and the temp while driving is rock solid. I'm leaving it for now and will keep an eye on it moving forward...

 

I am fighting the same problem, on my corvette it was an issue of coolant leaking onto the exhaust system, I suspect the sensor on the bottom of the resovoir tank on my 04'. I may try loosening the sensor and putting a fiber washer on it to see if that helps. That sensor is a twist fit and somehow it may start to leak after time.

 

I'd be afraid to use stop leak especially with the DCCV and the way it's designed. It doesn't seem to take much to make it fail and putting stop leak in may accelerate it's problem by clogging it up.

 

Every time in the past when I smelled antifreeze around my cars, it was the issue with the heater core. Just saying.

 

There is a rubber heater hose that runs down the valley of the V under the inlet manifold. A small leak here would pool and evaporate before it got a chance to leave a trace.
Also I have had an extremely small, hard to find leak from one of the plastic joints in the heater hose 'octopus' just above the bellhousing. This also tends to evaporate before hitting the ground!

 

There you go. Whenever there is a smell, but no evidence of the leak, heater core is a good place to start.

 

I had the same issue and spent a lot of time looking for it and could not pinpoint the leak until the upper rediator hose blew off the distribution pipe. The plastic had disintegrated inside the hose so I couldn't see it. I was lucky the hose blew off while parked so no damage to the engine. Inspect the distribution pipe and thermostat housing by removing the hoses.

 

There are two current threads on the forum regarding 308s that had a coolant leak rapidly turn into a destroyed engine, so, find it and fix it. Your temp gauge will remain centred until 230 F, then it will go up, and at that point it may be too late.

 

Never use that horrible stuff in a Jaguar engine!

 

Johnro....when was the last time the coolant pressure cap was replaced?
Are you sure you are not overfilling it?
Correct level is just base of filler neck....any more and it will dissapear into the atmospheric catch tank buried down in te left inner guard area.
If with a pressure check, you have discovered no leak I would just keep an eye on it and check fluid level when the engine has cooled overnight.
Tracing coolant leaks on these engines can be vexing and often is down to overfilling or a defective pressure cap which should be replaced every three years along with the coolant change....same goes fore the thermostat.
These engines were designed to allow rapid warm and heat exchange and keeping thesytem up to par is paramount but it's rare to actually have severe coolant leaks unless it has not been maintained properly as per correct service schedule.

 

Never could find the problem the engine seems to run at the correct temperature. I had it checked out no one seems to think there is a problem. The cap seems OK I will grab a new one and put it on to be safe. So far since Feb no coolant has been needed, still smell the coolant smell occasionally. I parked the car over a piece of clean card board to see if anything was leaking and there wasn't a thing on it. I just got a notice that is due for service so I'll let them go thru it and hopefully they won't find any problems either.

 

Lately I started smelling anti freeze again this time I tracked it down. There is a very small crack in the plastic Thermostat housing. For some reason it doesn't seem to show up with a pressure test. If it wasn't for a little puddle right under it I would not of noticed the little drop forming on the inlet. Found an aluminum replacement kit URO AJ82217KIT online for $46.09 at Autoplicity. I will be replacing the crappy plastic part sometime this week. Did a little research and the job is very easy.

 

Hi, don't want to alarm anyone... but I was told that the heater hose that runs under the supercharger on an XJR is a prime suspect!!
Warrick.