Hi all,

I own an XJR, early 1995 that has experienced an intermittent smell in the cabin ever since I first acquired it back in 2009. I've had garages look at it now and again, but none have found the problem.

I'm fairly sure it smells of coolant, (smells kind of syrupy), but i'm not certain that it's the heater core, but probably something nearby. There is a hint of the smell in the engine bay driver side, but not strong.

The smell comes in the cabin when the engine is warm. I can drive sometimes long distance and never smell it. It can be there for 20 minutes really strong (overpowering) and then it goes again. It doesn't correlate to when I have the heater or AC switched on. It is there even with AC and climate control switched off. I don't get any fogging inside or puddles on the floor.

The strange thing is, if I put the air on recycling, the smell disappears and both the heater and AC work normally without the smell. I often drive long distances pressing the recycle button every 5 minutes to avoid the smell. If the heater core had a problem, surely the smell would persist if using the heater?

I would really like to know if anyone could suggest where this smell could be coming from, it takes away the fun, and is probably why the car has always been low mileage (75,000 km to date).

Thanks in advance!
Oliver

 

I once owned a 1995 XJR as well. I went thru a 2-3 month period of smelling hot coolant. Just a whiff here and a whiff there; sometimes in the cabin, sometimes not. Never constant. I had one helluva time finding the leak. It ended up being the gasket between the cylinder head and the thermostat housing. Very small leak.

Cheers
DD

 

I have the same problem. Cannot pinpoint. I did have a coolant leak from the upper hose that used to drip on to the engine. Suspect some residue still left and burning when engine is hot. I am getting the engine detailed soon.

Another suspect could be dirty evaporator coils.
https://www.google.com/search?q=clea...w=1024&bih=648

 

The fact that the smell goes away when you are on recirc, and the heater and AC work normally sounds like a very good clue that the smell is coming from outside the cabin, rather than inside, so heater matrix, evaporator, damp carpets etc should move well down the list of suspects for the moment.
Concentrate on the air inlet area for the cabin, at the back of the engine bay. Check it isn't full of debris, old leaves etc. Try running the engine with the bonnet open while sniffing; if it smells of coolant....... !

 

The hose on the back of the engine-driven coolant pump below the intercooler might be leaking. Its hard to get at but you should be able to see a leak or residue.

 

Thanks for all the suggestions! I'm going to have a good look this weekend, especially near where the air inlet is. It would make sense, perhaps if drops of coolant are being blown into the air inlet and evaporating on the heater core, causing intermittent strong smells.

I will report back once i've nailed it.

 

I may have found the leak where the big hose that runs along front of engine joins the thermostat housing. There's dried white deposit around the pipe, and I think it's dripping into the metal 'bowl' beneath it, and then evaporating or boiling away when the engine gets hot.

I'll try fixing that and see if it helps.