Hi all, it's been a while since I've been here, glad to see the forum is still active.

My '05 S-type has been a great, great car for me over the past twelve months, but now I'm getting the (apparently) well documented coolant leak. The check engine light came on a few weeks ago, I had the codes checked & was told that it was due to random misfires, but no cause was determined. Then a few days ago I began getting the low coolant indicator, along with a small puddle under the car. I needed to wait a few more days to get the thing repaired so I just replaced the coolant to full level, but just today after a long drive I had a very hard time getting the car started (lots of coolant leaking suddenly, as there was smoke & coolant smell from the engine). After about 15 minutes of trying I was able to get the thing going, but idle was very rough, and at a couple points I had smoke come out of the exhaust for a couple seconds. I'm no mechanic, but my best guess is that coolant started running over the spark plugs & is interfering with them (and getting into the engine itself).

I guess the question is, has the leaking coolant already done severe damage to the engine, which will likely require rebuilding/replacement? This would be bad, but not as bad as having incremental repairs done to the hoses, ignition wires, etc only to find out that the engine is trashed.

I'm taking the car to a mech tomorrow, so any advice beforehand would be much appreciated!

Jason

 

If you've read enough threads here regarding coolant leaks in these cars, you know that the usual leak source is the poorly-constructed plastic coolant expansion tank. The plastic hose nipple fittings tend to become brittle, then crack, then leak. If this is indeed your issue, the fix is essentially a new tank....

If coolant is indeed getting into your engine, the issue could be very different, much more serious, and far more costly. One possible cause is a blown head gasket (rather rare on these cars). But if you're running ANY engine that is very low on coolant or perhaps even with no remaining coolant, blown head gaskets are the typical result....

 

I'm really not sure what's wrong. Sounds like 2 separate things (misfires and coolant) but are they linked? I don't think leaking coolant can go there on your engine?

 

jmcGoBlue:

I had the same large coolant leak at the mechanic's while reparing the a/c.
As mentioned above, the plastic parts tend to crack after a while. In this case it was the thermostat housing, which is made of this material.
At first we thought it was the water pump, the coolant leak was from the rear engine, but could not find the source until a proper inpection was done.

05 2005 Jaguar S Type Thermostat Assembly - Cooling System - OE Aftermarket - PartsGeek