I'm trying to isolate the source of a slow coolant leak. I haven't removed the airbox or battery tray yet. Coolant appears on driver's side under transmission.

1. water pump dry - bearing is good w/ no play/noise/run-out
2. new upper rad hose/thermostat
3. coolant recovery expansion tank new w/ good cap pressure
4. no air in system (used pinch bleed method)

Any help, advice appreciated.

-Ace
2005 Jaguar X-Type Sport 3.0 - 95K miles

 

Almost certain its the o ring that seals the water pump outlet pipe to the elbow that sends coolant into the block, located between the 2 cylinder heads under the fuel rail and lower intake assembly. If not taken care of it will drown out the knock sensor and cause a limp home mode. When that seal leaks it pools on top of the block until it overflows and then pools on top of the transmission.

 

I read your reply yesterday and gave it some thought. Thanks for the quick reply to my coolant leak issue by the way.

My next question concerns confirming your hypothesis. In other words 'how do I find it and fix it'. It's Saturday and the SOCAL weather is fair with temperatures in the mid 60's which is a big plus.

Now, like all good Jaguar DIY'ers, I have a camera phone. So, for my next question: Is it feasible to take a photo of the outlet pipe area and post it to the forum? (Preferably w/o removing the air box, intake, battery/battery tray)

I forgot to mention on my original post that I checked for coolant leakage while burping the air out of the system during the last top up (with water).

So, for the moment, I'm fairly sure that no coolant is lost until the engine comes up to operating temperature (thermostat opens). This leads me to believe the leak is on the coolant return flow side and only occurs after the thermostat opens.

 

Take a flashlight, from the water pump side of the motor, since it up into the valley between the two cylinder heads. It's a tight area but at the right angles you can see in there...if it's that o ring i am talking about there will be coolant pooled up in there. You can also see into the valley from the accessory side but it's tougher to get the right angle.

I only suggest that oring because it failed on me and it did indeed drown out the knock sensor after letting the leak go and just keeping an adequate coolant level.

My indication of a leak was exactly as yours, I had coolant pooling up on top of trans under the hise that feeds the pump from the tank. My first thought was the hoses around the area. They all seemed good so I looked closer and I could tell from staining that there had been coolant running into the pool from a higher point. Chased it into that valley and bingo!

 

Hahaha man I just went back to re read your original post. Sorry! For some reason I thought you said it was on top of transmission not under...

My apologies!! That'll teach me to put my nose where it doesn't belong! Haha again, I'm sorry! Someone else might be able to step in and save the day now haha

 

G'day Ace,

I had a similar problem and it was the 'O' ring in the elbow. You'll have to remove the engine cover, oil filler cap and three screw fasteners, and the elbow should be obvious, LHS facing the engine with the hood up. Drain the coolant and remove the coolant hoses and there is only one bolt holding the fitting to the elbow. Easy peasy.





Coolant Elbow.

Cheers,
Jeff.

 

That's quite alright. In fact I'm going to check the location you mentioned tomorrow just to be sure.

Maybe I caught early?!?

 

Thanks Jeff and everyone else with advice on my hiding coolant leak problem.

I'll check that area and related hosiery for the $$ pink Jag sauce. Maybe post some photos later for good measure.

Oh,..I hope you have a nice week-end too.

 

Is there not some small coolant lines that connect to the underside of the throttle body?

 

Does anyone know the part number or exact size of this o-ring? I am 75% sure I need to replace mine (water in the "valley") but would like to have it before I take it all apart...

 

I would like a reply with the o-ring part number as well; and exploded view illustration (if possible).

 

C2S5121 is the o ring for the water pump pipe

XR85431 is the gasket that seals the elbow flange to the block. You'll need this if you're replacing the knock sensor...

Can't really find an exploded view that shows anything other than the replacement part exploded views. Nothing of the actual valley area exploded.

 

Thanks for the replies and o-ring information. I am replacing the water pump, belt tensioner pulley, and belt. I'll tackle the o-ring when I pull the intake to install new iridium spark plugs/intake gaskets.