Overheating → Cracked V Pipe → Cylinder Head Woes – 2016 V6 3.0 Supercharged (Help/Advice Needed)

[declang123]

Hi all,

Looking for some Jaguars-savvy input after a run of bad luck with my 2016 V6 3.0 Supercharged (RWD). Here’s the timeline:

It began with overheating, which I later traced to the cracked plastic V pipe under the supercharger—apparently a well-known weak spot on these engines that often fails catastrophically.

I caught the overheat on a fast A-road, but only properly noticed after the system dumped most of its coolant through the failed pipe (pressurized and sprayed everywhere). As soon as I realized, I immediately pulled off, shut the engine down, and left it off.

I didn’t restart or run it again until the faulty pipes could be replaced (I’ve now upgraded them to metal replacements).

Once everything was back together and topped up, I checked the system—now it’s bubbling up into the coolant reservoir straight away.

So far, specialist advice suggests there’s now a crack in the cylinder head (likely from the overheat incident), and the usual "new engine" talk has started—way out of my financial reach.

Has anyone had luck with cheaper or DIY fixes after a supercharger pipe failure led to a head crack? Specifically:

Any positive (or negative) experiences with chemical sealants (K-Seal, Steel Seal, Bar’s Leaks) when bubbling is present?

UK sources for used/rebuilt AJ126 cylinder heads, or suggested breakers/scrap yards?

Realistic indie garage or mobile mechanic repair costs for this scenario?

Any input—especially from anyone who’s survived a similar chain of failures—would be massively appreciated. Really don’t want to scrap the car if there’s still an affordable route.

Thanks!

Dec

 

[RPSN]

Hi,

A quick online search produced this...

F-Type coolant bubbling most often signifies a severe issue like a blown head gasket, where exhaust gases leak into the cooling system, or a blocked coolant system due to air pockets, which can stem from air in the system after a flush, a bad radiator cap, or a faulty component like a water pump or thermostat. Other potential culprits include leaks from the Y-pipe or an issue with the electric fan not working. Because bubbling can lead to serious engine damage, it is crucial to stop driving immediately and have the problem diagnosed and repaired by a qualified technician.

Common Causes of Coolant Bubbling...

Blown Head Gasket:
The most serious cause, where exhaust gases escape into the cooling system, creating constant bubbling.

Air in the Cooling System:
Air pockets prevent proper coolant flow, causing localized boiling and bubbling. This can happen after a coolant flush or if there are other leaks in the system, such as a failing water pump seal.

Faulty Radiator Cap:
A damaged or loose radiator cap won't hold pressure correctly, allowing air in or causing the system to lose its seal.

Thermostat Failure:
A stuck-shut thermostat will prevent coolant from circulating to the radiator, leading to overheating and bubbling.

Electric Fan Malfunction:
If the electric fan isn't working, the engine can't be cooled efficiently, causing the coolant to boil.

Coolant Leaks (e.g., Y-Pipe):
Leaks in components like the F-Type's known Y-pipe can let air into the system, or cause coolant loss that then leads to overheating.

What to Do...

1. Stop Driving Immediately:
Bubbling coolant is a sign of a critical issue, and driving further can cause severe engine damage.
2. Allow the Engine to Cool:
Wait for the engine to cool completely before attempting to open the radiator cap or check for leaks.
3. Check the Coolant Reservoir:
Look for bubbles in the transparent surge tank.
4. Perform a Pressure Test and System Bleed:
A professional technician can use a pressure test to find leaks and bleed any air from the system.
5. Seek Professional Diagnosis:
A technician can check for a blown head gasket using tests like a cylinder leak-down test and inspect for other issues.