Hi there, I think the engine coolant system on my 1997, 550 Marranello is leaking. How can if find the source of the leak? Symptoms : When taking a long drive 2 days ago, the engine was over running at excessive temperature. Next day engine warning sign came on (water temperature). Expansion tank which holds the coolant was empty. This was fully replensihed with approx 7 litres of coolant, the system was bled and it seemed ok. Next day (today), the coolant level in the expansion tanks is right back down again. Apart from stripping down the entire engine block (which is a bit too complex for me), how can I identify where the leak is coming from? Many thanks for any ideas or suggestions. Best regards, Joel K, Leeds, Yorkshire, England.
That does not sound good, but let's try some thing simple first. 1. Do a coolant pressure test with a tester. Do you notice any leaks? It may be simple as that.
Big Question: is there a puddle under the car ? If there is a puddle then try to follow the drip backwards and upwards until you can see where it's coming from. Maybe a damaged hose, band clamp, core plug etc. If there is no puddle then you could be in for a rough ride (financially speaking). If it overheated you may have a cylinder head leakage issue or similar. Do you get a lot of water vapour in the exhaust ? Have you looked at the engine oil, is it clean & 'dry' or emulsified ? 7L is a lot of water to go missing. As yelcab said, pressure tester is a key point here. Read the instructions with the kit and it will give pointers on diagnosis methods and test procedure.
The best way to check the cooling system is to use a pressure tester. You can get them at any auto parts store. How they work is buy removing the the pressure cap and then attaching it to the radiator, or in this case the expansion tank. Then the system gets pressurized. There is a pressure gauge on the tester that shows the psi being put on the system. If you watch the gauge you'll be able to see if it is holding or loosing pressure. While the system is pressurized you can also listen for any air that may be leaking out of the system.
Hi....... As I recall, there is a fluorescent leak finder on the market. Add the chemical to the coolant and use an ultraviolet light to pinpoint the leak. Not sure, but try a Google search for it. A pressure tester will tell you that you have a leak, but not pinpoint it, especially if it is an "internal" one. Good luck !! Frank.........23005 www.masiarz.net/bb_resource
Eastwood sells UV leak detector kits, as do most auto parts stores. BTW, if you're pressure testing, 10-12psi s/b sufficient. Don't go over 15 PSI or you may burst something.
Testing for a head gasket leak with the loss of this much coolant would be fairly easy. I doubt that that much coolant would being burned in the combustion process without the car running poorly. Which leads us to the easy test. Change your oil. If you have a head gasket leak odds are it'll either be leaking into your combustion chambers or the coolant is mixing with the oil and vice versa. Seven liters of coolant would be fairly easy to find in the oil if that's the case. If it's not mixed up and you still can't find an external leak then it may indeed be leaking into the combustion chamber. At that point start pulling spark plugs and look for the fouled one(s). I doubt this is the case though. From what I hear these engines are fairly bullet proof. Also, I just remembered this, it may be your radiator cap. If it gets weak the system won't pressurize properly. As pressure builds in the system the cap will open and dump out fluid. Which would explain the loss of yours. Also because the system can't get up to pressure the car won't cool properly. Radiator caps are fairly inexpensive. You might just run out and buy a new one and put it on then see how it runs. Keep a close eye on that temp gauge though. If it gets too hot then you could be looking at head gasket problems.
A 97 550 was built with those trash quality hoses under the intake manifold. Refill the cooling system, you may not even have to pressure test it and look for water under the intake manifold and running down the back of the motor and over the clutch bell housing. If it is those, find a new mechanic. He should have known about them and changed them a couple of years ago to keep you from getting stranded. That is his job.
As prev mentioned, can only be an internal or external leak, but the differences in fixing are huge. Put coolant back in & take for drive. Pull over occasionally as warms up, keeping engine running. An external leak is gotta show soon enough when up to temp. Hope for a leak! Note that a head-gasket leak can chew water both internally into cylinders and externally by pressurising water jacket & bubbling coolant out of the expansion tank. Keeping the radcap off during warm-up may show frothing of the coolant. I'd try a cheap (temporary) rad-cap replacement of same pressure rating first. If noting else it may "encourage" the leak to be more obvious (as if 7L isn't enough!).
If no external leaks are visible, I'd be very leary of running the engine until I knew where the leak is. If it's internal into a cylinder, you may be looking at hydrolock. If that happens, poof.....there goes the engine!
Hi Fellas, Thanks for all your advice. If any of you want "closure" - I found out what the problem is.. The Water Pump has packed in.. Apparently a fairly common fault of cars of that age... Next problem is making sure the dealership replace it under the warrantee ! Cheers for the guidance ! Regs Joel.
Thanks for the update. Glad it wasn't anything serious, and it was found before something serious did occur!
WOW the water pump hu??? Glad to hear you go it figured out. Now get it to the dealer before the warranty expires.
