Seems I've got a new one. No overheating but the car threw an engine light. Then said COOLANT LEVEL LOW or something like that.

Checked and there was visible coolant around the edge of the lip of the reservoir top.... like around the base where it had collected, not at the actual cap. The cap was on tight. Multiple clicks, no problem. But indeed, the level was low. I topped up.

Then today I checked to be sure and again it was low. Coolant was again on the outside of the reservoir like it must've been thrown out of the reservoir while driving or something. Cap was still on tight. I cannot explain it. If the reservoir itself was cracked I would not expect that the coolant would migrate against gravity to end up above and on top of the reservoir. The only thing I can think is that somehow the cap itself has become defective??? Does this happen?

Would like to not have to be topping up weekly.

 

Yes.

And/or the gasket swells and fails.

My two use the same cap, so I order them three at a go.

BFD.

 

Thanks Bill. Sounds like it's time to spend some money.

 

Even after topping up last night with coolant, as far as I could tell considering that the car was in the garage and the overhead lights were obstructed by the bonnet, I managed to get the dreaded ENGINE COOLANT LOW and red light warning with 50km to drive home. Decided not to put the coolant bottle back in the car (of course) last night. So that was a fun drive. But motor temperature stayed fixed in the middle. So I was ok.

Today, now, it’s Amazon for a new coolant/rad cap. No more delay. I’ll run out of coolant before long. Only one gallon jug unopened and just 1/3 left of the opened jug. Glad I brought what was originally used from Poland with me. Something from the PLAK brand. It was cheap. Tesco purchase. Has done the trick all these years and the Polish mechanics did a flush a one fill with it for me and these were the surplus I had left over.


Engine coolant low, failed coolant cap in 2007 X350 XJR.

 

Not to forget - it is the symptom, not the disease. You still need to find the causitive leak that over-cook's 'em in the first place.

 

Don’t believe anything is overcooking anything actually. I was poorly/imprecise in using the misspelled term volcano 🌋 in referencing what was going on. But there was a bit of spillage just around the outside of the cap itself. Since the cap was clearly no good, coolant was able to work its way out of the reservoir around the cap and then during driving it would be jostled or vibrate a bit onto other areas. Be thrown more or less. Not a huge amount but some. Fluid would also collect around the bottom of the reservoir lid, just on the lip. So that might also get tossed around while driving.

Since I couldn’t see properly last night when I went to add more I mustn’t have added nearly enough. Couldn’t check when I got home since I didn’t want a face full of steam. Will do it properly tomorrow AND bring the coolant jug with me. The cap has been ordered. Expedited shipping for Wednesday from Amazon. But overall that 400km trip I just took last week, no trouble but must’ve eaten considerable coolant.

 

Figured it out yesterday. Wasn’t the coolant cap. Had bought a replacement at Crappy Tire but still had leakage and loss. Two days ago drove into town and noticed fluid under the car after parking at a shopping mall. Couldn’t tell the colour though. Apparently I came to determine later that the coolant was collecting in the under-engine cladding and would only dump itself once full of coolant onto the ground. Happened again the following day at Walmart, this time could see the colour as it drained from under the car so was more visible. Topped up again and drove to go home. Not even 5 minutes later, driving over some very rough pavement in the road which I’ve already reported to the city several times… they decided to send it to Budget Committee instead of Public Works, and the low coolant warning came on. Smoke soon started to appear under the hood. Soon after at the next red traffic light the car started to jump in temperature. I turned off the ignition, waited 30 seconds with cars diving around me (thankfully we were already stopped) and managed to limp off the road. Waited 2 hours for a tow from CAA/AAA.

Tow driver checked and the plastic hose leading from the coolant expansion tank and sheared completely off. It must’ve been cracked previously. Right at the point where it was connected to the tank itself. So could not be fixed. Car is at the mechanic currently. Now I’ll have the original coolant cap, two more purchased this week and one more that comes with the new expansion tank. When it rains it pours!


Broken attachment area of hose to coolant expansion tank.

Tow arrives after a mere 2 hours.

Finally at the mechanic.

 

I did say "..symptom, not the disease?"

The disease, BTW is "too DAMNED much short-lived plastic in all the wrong places."

 

You did! And also true, to have such a connection point to be made of some clearly rigid or prone to dry/crack plastic was a bad idea. Riding on the Sepang wheels and with the crap roads, it was bound to happen. I’m tempted to submit a claim to the city considering I had reported the road precisely where the thing broke at least a week before and it’s on a major thoroughfare. A very poor prior repair job. That’s when it lost all its coolant and the light came on and the smoking started from the engine bay. Of course they will deny but it’s no different than a claim for blowing a tire on one of the many pot holes on the same road that they’ve still not fixed after my calls to 311 a million times.

 

New tank is an easy fix for that, but that vent hose will pump a LOT of coolant out very quickly if it's completely open! the large hose at the bottom of the tank is actually the tank's drain, where coolant exits the tank to proceed through the system. The spring clip on the bottom hose is a bear to get to unless you remove other hoses first to get them out of the way. I replaced all of my hoses, the radiator, and the water pump last summer, because i got fed up with blowing the next weak link after fixing items one at a time. I replaced the radiator, then the expansion tank split. I replaced that, then the water pump started spraying, At that point I started a complete overhaul, including the hose under the intake manifold (which turns out to be the only one visibly damaged by age.)

 

Thankfully, or not, the car is at the mechanic. Parts coming on Monday. He’s actually moved the car to his house for safekeeping in the meantime. Towed it over there. It’s at times like these that having someone you can trust and doesn’t cost the first born is a real asset.