Hi all, my 15 XK convertible has already lost an engine due to overheating. The new engine runs great, but had a coolant smell from the day I picked it up from the shop which wad attributed to residual spills etc., but never went away. I ended up having it pressure tested and was told hoses to the thermostat had a small leak so they were changed with the thermostat, but I still smell coolant specially on warm days. I see nothing on the garage floor, but think there are many seepages here and there. I know it is sacrilege, but what if I add a little stop leak to the coolant.

 

The under tray holds quite a bit of fluid. It could be nothing more that that. If you pressure tested it ad now it's fixed, that would be my next guess.

 

My slow coolant leak (see current thread) produced a smell of coolant but did not produce any drips on the floor. The lost coolant is accumulating in the bellhousing!

I doubt very much whether anyone else in the world is experiencing this particular problem but pulling aside the edge of the rubber grommet in the bottom of the bellhousing would soon allow you to rule it in or out.

Richard

 

Does the coolant level in your expansion tank drop appreciably over about a month or so? If it does (or drops faster than a month!) then it’s time for further testing. If it doesn’t drop (or drops very slowly over a timeframe of many months) then don’t worry about it. Just monitor the expansion tank routinely.

 

Any coolant leak, regardless of severity, should not be overlooked. Cooling systems are the weakest link to Jaguar ownership and can lead to catastrophic destruction of engine with at times very little warning. It’s prudent to address all coolant leak symptoms.

 

I'd avoid any stop leak product. When my new-to-me 2015 XK wouldn't put out heat on my delivery trip home (purchased in FL, I live in VA), dealer said the heater core is plugged. After a rather expensive repair (replacing entire heater box), I now have heat. The techs confirmed "previous work" had been done on the cooling system and heater core was plugged. If there's a leak, fix the leak properly.

 

Does this mean my heater core is blocked/ bypassed?

 

It's certainly bypassed, as you can easily check if you can park somewhere cold enough to test the heater in the car. Why it's bypassed is unclear. Probably a leaking matrix/connector rather than a blocked matrix. You could reconnect the hoses and see what happens although I don't suppose that the loss of the heater is of any great importance where you live.

Richard

 

Thanks Richard for the info.

Yeah, being stuck in the desert means I don't even need the heater.

That does make me wonder though, could this affect the engine cooling? Even though the heater's off, the coolant's still circulating through those metal pipes, and that bend in the tube seems like it might mess with the flow, wouldn't you say?

 

The heater matrix and its pipework does relatively little cooling compared to the main radiator when the relevant vents are closed so, unless there is a problem with the main system and it is operating at marginal efficiency, then I wouldn't worry about the bypass.
I also believe that even a complete blockage of the heater system would not affect the circulation through the main system. However, if even I didn't wish to conduct further tests to see why the heater has been bypassed, I personally would replace the bypass hose with something which allows flow if the current bypass is stopping flow. You could test this by feeling the temperature of the hose on either side of the bend as the engine is heating up. My reason for wanting flow is that sediment may accumulate and harden in the "dead run" over time which will might make it more difficult to reinstate the heating system should this ever be desired.

Richard

 

Ken D. I also always smell coolant and I am 100% positive I have no leaks. Coolant level is stable and has been for months. BUT and maybe it's just me I still smell hot coolant after shutting the car down. I now think it's just part of how these cars work?
I do have a different car (2104 XJR) but I smell it too!
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So if the heater matrix is blocked, plugged you have no, or very little flow from the rear heater manifold. The 13mm outlet, just the 5mm vent to the expansion tank.
Did they say what it was plugged with rad seal/stop leak, or mixing the coolant with none Oats type?

Either way putting stop leak or some such as you say is not a good idea.

 

Any coolant leak generally is progressive. Even one or two coolant drops off a hot surface will cause a coolant smell to emanate. Coolant smell is not normal for jaguars. The only time my 2010XK had no coolant smelll was when it had 4,000 miles and last year when I replaced every coolant pipe, connector, etc. I should be good for 6-8 years. Small coolant leaks don’t go away.

 

The heater matrix was indeed blocked by some type of stop leak crap.

 

I have had Jaguar's for about 15 years now and yes coolant smell is normal and constant. I have zero leaks as confirmed by my pressure tester.
It's part of the experience.
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Not saying that everyone will have the same experience with coolant leaks, but I have a leak that I've been trying to trace off and on for over a month. It absolutely doesn't show up with the engine cold and a pressure tester fitted to it. 29pps for over 12 hours and zero leaks. But if I take her out for a spin and start getting the revs up around the 6k mark, the coolant will indeed begin leaking. Sadly for me, not enough for me to see active dripping after the spirited drive and parked at idle. Hence, why it's taken so long to diagnose. Bottom line, I wouldn't say that it's safe to always trust a pressure tester with every type of coolant leak in these cars. Cheers.

 

Mine always has a smell after a drive , never seems to go down though. Thing it might be the overflow cap, just a guess.

 

The coolant system is a closed system. No CW loss expected.
If there is a loss, you have a leak.

The smell of coolant, subject to no coolant loss, therefore cannot be an ongoing coolant leak, but some other odour, or an old Coolant leak odour! Plastic, under engine sound deadening, drying off after a car wash or raining.

Or indeed, coolant water from a previous leaks still leaching out for the surrounding materials. So yes possible to have that lingering odour.

A pressure test is a pressure test, and the system may be holding up to this pressure when cold. When hot and running, the materials can expand, and move and leakage may occur.

Searching for a minimal leak for a month! Is relatively short when the pressure test is not telling you anything.

The key suspects are:
The water pump telltale, dripping CW and being blown back into the valley vee and drying before any pooling can occur.
The thermostat housing cap seal, weeping. Which I eventually found after 5 months plus, and JLR failed to find by pressure testing etc.

During the repair I was very careful to wash the valley Vee clean of all CW residue, and wash the engine cover, and the under bonnet material. ( The 3.0SC does not have bonnet vents)

There is nothing like the Smell of NOT having coolant water odours in the morning, To paraphrase Apocalypse Now.

 

Small coolant leaks generally will not show up on a pressure test. When my front outlet pipe was seeping the pressure test always held. Yet after 1000 miles I added 2-3 ounces. Very little loss but still a leak. Of course if the seams of that pipe opened during a complete failure of that pipe ( which does happen)the state of my engine would have been jeopardized. Only with a boroscope and removal of the intake did I see the red staining from the seepage.

 

Can you actually see any pink residue anywhere on the engine or coming out from on top of one of the undertrays? If not, try removing one of the two rubber bungs in the bottom of the torque converter/ flex plate bellhousing and stick you finger in there. If it comes out pink, you have the same problem as me!

Richard