Hi,

Despite having a fully charged battery (been attached to the C-tek) the engine initial turns over once then stops dead. I release and re apply the footbrake and then it continues to turn over before starting on each and every occasion. Starting the car within a couple or hours if not the same day the issue does not occur. I have for the last couple of weeks also been battling with a small coolant leak and what appears to be internal (I have been unable to find any coolant leak under the car or in and around any part of the engine bay). Could the start of what might be a blow head gasket be the most likely cause of the internal coolant leak (or there many other possibilities) and would coolant in one of more of the combustion chambers cause the initial halt of the engine turnover.

In addition to the valuable advice that may be given here, would a compression test, leak down test or coolant pressure test (or all three) be the way to go in ascertaining more data on the likely cause of these two issues. Are they other tests or observations that can be undertaken.

Many thanks.

Colin.

XKR 2007 - 150k on the clock

 

Does the starter stop AGAINST something, or does it just stop electrically? Does it stop cranking, wait a second, and then a very minor 'release' sound? That'd be something mechanical.

 

I thought the last XKs and XKRs were built in 2014. How did the OP get a "2017" XKR?

 

I assumed it was a typo, should be 2007

 

Thanks for the prompt reply Cee Jay. Will start the car this evening (I’m in NZ) and take note of the exact nature of the engine stopping with a view to answering your questions.

Thanks for pointing out the typo ralphwy, should have read 2007. Now updated.

 

So as per my reply below to Cee Jay I've just been out to start the car- its been sat there for three days and its started first time!

However (and until the car misbehaviors again) in answer to the question posed and what I observed previously - the car would just crank one but would stop dead even with my foot held firmly on the brake pedal for several seconds (a will hold the footbrake down for 10 seconds or so next time it fails to start). I did not notice any electrical clicking (such as a relay or co) but from experience in HVAC systems and the such it reminded me of the effect of a hard object hitting a body of water with a confined space, (I did however not feel any shudder in the car) And to why I considering water in the combustion chamber as one possible cause.

 

Had a faulty earth once which affected the starter. I’d assumed it was the starter or the solenoid failing until I located the actual cause. You can test the voltage/current going to the starter

 

A scary thought, hinted at earlier, is that you do have a leaking head gasket. As the engine sits after a run, the pressurized cooling system is slowly pumping coolant into a cylinder. When you try to crank, the piston comes up against the water and hydro-locks the cylinder. MAYBE then the water is slowly pushed out (I admit that sounds wonky) and allows the engine to crank normally. I'd like to think this is not what you are experiencing, and it is something (simply) electrical.

I gather you aren't seeing clouds of steam in the exhaust at startup?

 

I had Hydrolock in my P/S Mustang before, but it only happened after I first started and drove it, then let it sit for longer than five minutes and less than thirty minutes. The Power Valves in the carburetors were leaking, which drained the float bowls into the intake, which went into whichever cylinder(s) had open intake valves. It doesn't take much, either. A few cubic centimeters of liquid can play havoc with a 40cc chamber made for A/F mixture.

 

Colt23, if you have an internal leak and thereby water in the cylinder when attempting to start, you must get it fixed. You risk bending a connecting rod, yes fluids cannot be compressed, and starters are strong.

Here are some suggested steps. If any of the steps are bad, don't go on, don't start the car, pull the head, fix the problem, or you'll end up hurting piston/connecting rod::
-Check engine oil, any sign of water? Mayonaise like?
-Check coolant, any sign of engine oil? Must be clear and orange and not mixed with darker slimy stuff
-Check compression, remove all 8 plugs. Any cylinder lower than the rest, or maybe 2 adjacent cylinders?
-Put pressure tester (Summit thing or similar) on radiator. Hand pump pressure. Must be able to retain pressure when engine off for an hour
-Keep pressure tester on, start engine. If tester needle bounces regularly, leaking head gasket

Hope it's nothing serious, but if it is, you risk making a problem a lot bigger if you keep starting it. Good luck

 

Thank you for the valuable feedback and have certainly taken onboard your advice No Quarter about the risks of continuing to starting the car.

Have checked oil and coolant and no signs of the the two fluids mixing in either the oil cap or the coolant reservoir. With regard to further test (and in addition to the pressure test on the radiator) would a Leak Down Test as opposed to just a Compression Test yield more definitive results as to the condition of the engine and specifically whether the head gasket has blown.

 

A leak down test will probably be just as good as a compression test for this purpose, will one or more cylinders leak faster.