So I have been driving my somewhat newly acquired car (69 roadster) maybe a few hundred miles a year. I have a pretty good understanding of issues that need addressing, save for one… and I hope its not as bad as i think it could be. I think all these symptoms are related:
-Lots of coolant gurgling when the car is shut off. Occasionally the upper radiator hose will collapse.
-There is some indication of oil and water mixing in the crank case breather cap on the front of the motor.
-Sporadic vapor coming from exhaust.
-Seems to be positive pressure in crank case. Oil is seeping past the dip stick and getting on the exhaust.
-There is a bit of clatter when free reving through ~2000rpm
Ive worked on lots of motors, MGB, Bmw S52, to name a couple, I feel like this is possibly a serious problem, but being mostly unfamiliar with this motor Id like to see what others think is the best place to start. The motor was fully rebuilt in 2016… I dont feel like its seen enough use since then for it to be worn sleeves or rings. But i just do t have enough working knowledge of the systems on this car to do much visualizing of whats going on inside.
Rather limited information on the history
By who ,how long have you owned it ,is this something new
You should do some testing as a start IMHO
compression
Leak down if you can
Pressure test cooling system
And go from there
Was the head re torqued?
Changing a head gasket is relatively easy if it wasn’t torqued correctly ………
Coolant is getting into the exhaust
And oil shouldn’t be coming out the dip stick pressure from somewhere internal
Collect more information before diving in may save a lot of work
There are two types of caps in your cooling system, a blanking cap and a pressure cap. The blanking cap goes on the radiator, the pressure cap on the firewall mounted header tank. Important they are not reversed. Also check that you do not have two caps the same. Blueskying here but the rad hose collapsing indicates the cooling system is going under vacuum as it cools down, so pressure is being released when the coolant heats up and expands but is not equalising while the coolant is cooling down after shutdown.
Vapour out the exhaust is not unusual on startup. It’s from condensation in the exhaust. There will also be condensation in the block, which can manifest as a greasy white film on the breather. The screen needs to be kept clear, else pressure can build up in the crankcase and exacerbate oil leaks, particularly out the rear rope seal and cam covers. Oil on the exhaust will more likely indicate leakage past the cam cover gasket or from the camshaft oil feed pipe banjos, neither requires excessive pressure in the crankcase.
XK engines are typically a little noisy. Excessive clatter is almost certainly timing gear related. Remove the cam covers and check the upper chain tension on both outboard sides with a long screwdriver. It should be snug, not dead tight but not sloppy either. It would also be a good time to check your tappet clearances. An excessive gap can increase noise. While you’re at it, examine the tops of the tappet buckets for any indication of contact being made with the camshaft lobes, particularly on the exhaust side. If so, it will indicate a bucket coming loose. Caught in time before real damage is done it can be addressed with a tappet hold down kit.
Thanks for the responses fellas, this gives me some direction at least. To address the questions, the engine work was done by Autosport in Seattle. I inherited the car from my late father unexpectedly, so I am kind of figuring out what is what as far as what he had done recently, what kind of issues were not addressed etc. Im very familiar with the car as I had helped him put it back together after the rebuild, but don’t really know much about what kind of “deferred maintenance” or creative engineering was performed or not performed in the following years.
Thanks again, Ive bought a block test, and will check the radiator caps. The car does not billow white vapor while driving after the engine has warmed which has been my experience with blown gaskets… but I will test it. Also the oil is almost certainly from the dipstick hole, I wiped down the sides of the heads and the entire side of the block and the first place sheen appears is around the dipstick. I made a new felt gasket for it and it was immediately soaked, and no sign of oil coming from above down the side of the block.
Right beside the dipstick hole is the lower banjo for the camshaft oil feed pipes. Leakage is common there. Each of the banjos, top and bottom, are fitted to the head and block using two copper crush washers that in my experience lose their seal after many years and cycles. Check that out, too.
Progress is being made … as mentioned by both Nick and Tom the cap on the radiator should not be pressurized - neither of these caps are correct for the radiator on your Series 2 car. You need a non-pressurized blanking cap on the radiator. The expansion tank has either a 7# cap for non AC cars or a 13# cap for AC cars. I’ve read on other threads that a good quality blanking cap can be difficult to source and the ones supplied by the usuals were prone to leaking. Someone mentioned Waxstat brand (made in England) and Mini Mania for good quality replacements - others with more current info may be able to assist on a good brand & source.
Ok awesome, thrilled to have solved some part of the mystery! Much appreciated! Sorry I did not realize that a blanking cap was literally just a sealed cap.
hopefully the cap issue solves it, rad hose collapsing was a weird issue needed immediate attendance
Have the head nuts been re-torqued if since engine work
salad oil inside engine filler cap needs monitoring, I would consider changing oil and coolant
a leaking head gasket will sometimes reveal itself with careful observation of coolant in rad neck…it should not bubble when engine is running and up to temp, cap off
Once new oil and coolant are in place the most definitive way to monitor any suspicion is via test presence of ex gases in coolant, or coolant in oil
Sounds similar to an issue I had a while back… turned out a careful retorque of the intake manifold solved it! Check to see if you see antifreeze in the carb throats…
Ok, so I replaced the radiator caps with the correct ones, and did a combustion leak test and that did no reveal any leaks.
Still seems to be something strange going on with the cooling system though. When the upper hose collapses slightly while the engine is running there is a sustained honking sound coming from somewhere on the front right of the engine. I retorqued the intake manifold and it maybe has eliminated that sound, but the upper rad hose still collapses a bit when free-revving the engine. Is that normal? This car has triple SU carbs btw.
One ignorant question I have is that i don’t understand what the coolant rail running over and connecting to the tops of the intake manifolds is.
Your profile indicates that your E-Type is a 1969 model (Series 2) but you also indciate that you have triple SUs, so it has clearly been modified. Your reference to a coolant rail running over and connecting the tops of the intake manifolds suggests that you have intake manifolds from a 3.8 (3 separate manifolds) rather than a one-piece 4.2 “log” manifold. If so, the hot coolant emerges from the top of each intake manifold and into the collant rail. From there is passes forwards through the thermostat and on to the radiator (thermostat open) or to the water pump via the bypass (thermostat closed). There is also a connection at the rear of the coolant rail that goes to the heater, with the returned water from the heater passing under the carbs back to the water pump.
Yes this car was running triple Webbers for most of its life… it has headers, cams, light flywheel port and polish etc. Engine was rebuilt in I think 2016 and switched to SU carbs for usability.
Could there be a clog or restriction in the cooling system causing problems? Should there not be any pressure or vacuum in the cooling system whatsoever? My MGB cooling system is rudimentary by comparison. And my M Coupe cooling system is a closed system… so I am not sure if I am being fussy or not fussy enough about this!
The cooling system will become pressurised as the engine warms up. You probably have a 7lb pressure cap on the radiator. The collapsing top hose is an issue that needs to be addressed. As you have a 3.8 intake manifold mixed with what is probably othersise a standard 4.2 Series 2 cooling system, there is potential for incompatibilities in the design. Many have done the changes and made it work, so I bow to their experience - hopefully someone will chip in who’s been there…
