Hi All,
I wonder if you can shed some light on the following...
a 2015 F-Type S 3.0 V6 S/C Coupe A/T....driving car and the water pump and pipe had issues which resulted in a loss of coolant..kept topping up with water....no overheating warning came on.
Sent vehicle to Jaguar and they repaired the vehicle pump and pipe.
They then did a Block Test and sent me a quote to replace the entire engine due to the vehicle failing the block test (Image below) which apparently indicates a blown head gasket.
They have ran a compression test and a water leakage test and nothing is untoward on those tests....
Car is not misfiring at the moment....can someone give me advice on what to do....

 

The block test is to test for combustion gasses (specifically CO2) in the coolant.
The testing device is placed in the coolant expansion tank opening (you can just see it on the far RH side of the pic) and while the engine is idling a bulb on the device is squeezed to draw any gasses present into the special liquid in the device. If that liquid turns from blue to yellow it indicates excess CO2 in the coolant.
The liquid in the pic is definitely yellow, so if it is legit and they are not playing games the coolant in your engine has excess CO2 in it.
That is a tell-tale sign of a blown head gasket and/or a warped cylinder head, which makes some sense given the water pump and coolant pipe issues you describe.
Usually there has to be fairly severe overheating to blow a head gasket and/or warp the cylinder head but this is not unknown on the AJ126 and AJ133 engines, it doesn't take much for them to overheat with little or no warning. If/when that happens the engine almost always is toast seeing as both the block and cylinder heads are alu alloy.
All that said you should definitely seek a second opinion before shelling out several thousand $ on a new engine.

 

Does it over heat right now

 

I hope I never have to consider a new engine, but here is a possible resource for you if you do:

https://www.jaguarforums.com/forum/f...0-tapa-252798/

 

I have not driven it yet, the car starts okay and there is no misfire on the engine that we can pick up…i will tow it tomorrow to my mechanic in order for him to start it and will check if it’s overheating.

 

You might just have a weeping leak somewhere, mine will lose coolant on long trips or stop and go traffic. Think it is leaking either at the S/C or water pump, as I cannot find a leak. These cars leak coolant from so many places, it could be just a couple of small leaks that add up and WHY would they suggest a replacement engine, did they base it on anything, like coolant in the oil?

 

I may well be wrong but doesn't a compression test indicate whether you have a bad head gasket?

 

Poor compression in one or more cylinders could be due to a range of things not just a blown head gasket.
The most common cause seems to be stuck open/cracked/chipped/bent valve(s).
You can also have a blown head gasket but still pass a compression test, which seems to be the case here.

 

They didn’t base it on any other symptom other than this block test. The coolant and oil are not mixing, the car does not have any misfire or erratic idle.

The coolant was leaking due to a fault water pump and hose which has now been replaced and seems in order. It’s just a matter of wether the head gasket has blown and damaged the engine…there is no evidence suggesting it has other than this block test which I was never familiar with prior to this.

is this Jaguar being over cautious and paranoid or is this a real concern…. That’s my dilemma

 

As I said before, seek a second opinion.
JLR never repair anything, all they ever do is fire the parts cannon up to and including a new engine, so in their world a possible blown head gasket = new engine required with no need for any further checking or diagnosis.
It also helps - them - that they get to charge a yuge mark-up on a new engine plus an exorbitant labour rate for a job that takes many hours.

 

FWIW, on Wheeler Dealers recent episode, a car they were working on supposedly had a blown head gasket. The block test described here is one of the ways he tested for that. I was intrigued as I was not aware of this procedure/device either.


Like any major human surgery, second opinion always a good idea. Too often techs just throw parts at a problem and hope it goes away.

 

Crazy idea and feel free all to shoot at me....try perhaps adding 1/3 of a bottle of K-Seal and repeat the test. If the issue goes away....who knows, maybe this is good for years and years. Have heard internet stories about the stuff....


https://shop.advanceautoparts.com/p/...cal&store=3461

Seems like a cheap thing to try. Anyone have a reason to think this is a problematic idea please feel free to shoot me down.

I used this on a Land Rover with the old buick-based V8 and it fixed it (92 RRC LWB, loved that thing)...ran for another 50k and never had an issue before I sold it to a Land Rover guru who knew I had used it and had no concerns....saved me a lot of money.

 

Somewhere in the garage I have one of those testers. It's probably been a dozen years since I last used it and any test fluid I have is probably bad.

The only thing the test does, as OzXFR notes, is indicate if there is CO2 in the cooling system. This is not necessarily a head gasket, but that is probably the most common cause for failure. With the engines I used to deal with other possibilities were a crack in the head, and once I saw a cracked block.

Another thing to check before busting out the checkbook is to look at the spark plugs. If at least one looks to have significantly less deposits that its peers, that would corroborate the results of the test. Access to an endoscope/borescope would let you see the piston crowns. A quick check shows one at Home Depot for $119, but I think the head is too big for the spark plug hole. I didn't search any further.

EDIT: I see one that connects to an iPhone with a 7.9mm diameter head for $28.00 on Amazon.

 

Recent video from Rainman Ray one of my favourite YouTube mechanics:


Different car/engine - Chrysler Pentastar 3.6 V6 - but identical scenario, holed plastic coolant tube, lost mucho coolant while driving, engine overheated and shut down.
No "block test" instead found coolant/water in one cylinder, misfire codes for that cylinder, diagnosed as probable head gasket failure and/or warped or cracked head/block from overheating, engine likely toast.
Should be easy enough to conduct the same test on the subject car, i.e. look for coolant in one or more cylinders using a borescope.

 

@davidreid Any update or solution? Currently going thru a similar thing sadly... same green fluid color when I do the test and intermittent white smoke coming from the exhaust.