Headgasket Gone?- Help I've Screwed up!! :'(

[Bryan Boyle]

Alright y’all I have an update for you! Yesterday evening I managed to get the car to my place of employment to start running tests. So far I’ve only been able to run a leak down test and it showed as follows:
80psi of pressure in
#1 74psi - 7.5% loss
#2 68psi - 15% loss
#3 62psi - 22.5% loss
#4 64psi - 20% loss

This leads me to believe that the engine is pretty tired, but it doesn’t appear to have had the head gasket fail. JB I’m going to start working through your list over my lunch break today. I can start with plugs and we’ll see where I can go from there. Today will be the first I can work on the car with daylight so that’ll make things a little easier. Dreamer and Kendo y’all have both mentioned timing but I’m not sure what overheating could do to affect that, but I may need to begin looking there. Clifton I agree with you it definitely seems like a vacuum leak, which has me worried that the head gasket may have failed between a cylinder and and the outside world, as opposed to into a coolant or oil passage.

I’ll let y’all know what I find!

Boy...if I found those numbers in a cold Continental aircraft engine, I'd llet the owner know and sign it off for another year...lol.

[Kendo]

What numbers would you expect from a freshly rebuilt engine? Though I suspect bedding in the rings would improve it.

[Bryan Boyle]

What numbers would you expect from a freshly rebuilt engine? Though I suspect bedding in the rings would improve it.

The numbers would change in a properly cared for engine as the rings rotated in their lands in the piston during use as well as the valve sealing, etc.  A one-time pressure test (using 80 lbs as a standard pressure) would give you a 'point in time', but not a true average reading, as well as was the test done ice cold after sitting out all night, or after a 2 hours speed limit run down the interstate. 

For me (and unless you're blueprinting and expecting it to stay blueprinted past the first 1000 miles) anything more than 85-90% (ie 65-72 on a single test) is not reason for concern, absent smoke, mayonaise, etc and a cut-engine spark plug check by the side of the road.  There are too many variables in a complex machine machine (absent catastrophic indications like a connecting rod out the side of the block or metal strewn along the motorway in its wake) to put an absolute stake in the ground around one set of readings; you have to take the whole measure to determine the condition. 

[DreamsOfA47]

Alright y'all after much more troubleshooting and swearing here's where I currently am:

Firstly the poor running was caused by a vacuum cap that had been knocked off of my intake manifold. The car is equipped with a weber DGV and the nipple that sits directly below the carb on the intake manifold lost it's cap somehow.

Now in regards to the overheating issues I have no idea what caused the initial teapotting of the cooling system, but now the car overheats every time. I'm worried that when I installed my thermostat I may have put it in backwards or it was non-functioning on arrival. At this point I've bled the system several times, even going so far as to pressurize it to ensure any bubbles would be forced out. I've also taken out the thermostat to remove that variable. I'll purchase one of those chemical kits that cage color to check for combstion gasses in my coolant, but at this point I believe that to be what's happening. I'm worried that the coolant is being superheated by an introduction of combustion gasses and the system simply is overwhelmed. Interestingly the radiator in and out hoses seem to be the same temp. Currently I have a new Chinese eBay radiator installed in the car so I don't believe the separating plate has failed and caused the coolant to bypass the radiator as the rad gets far too hot to touch.

I can't really see any other possibilities other than head gasket. any ideas I'm missing, y'all?

[Clifton]

I knew it wasn't a HG and I'm sure you have air in the system. An air pocket won't allow water to flow and your in/out radiator hoses will be the same temp. I had this problem with the top hose at the front of the frame exit. I put a bleed and then finally a 1/16" hose and routed it back to my swirl tank. Not saying that's your air trap but there is air somewhere. They also make a fill kit that uses compressed air to pull a vacuum on the system and fills it under that vacuum. You need to fully drain everything though.

[Grumblebuns]

Alright y'all after much more troubleshooting and swearing here's where I currently am:

I can't really see any other possibilities other than head gasket. any ideas I'm missing, y'all?

Is there any test that will eliminate a head gasket leak? Has anyone used the coolant sniffer tester, are they reliable enough?

[DreamsOfA47]

Clifton do you really think that there could still be air in the system? I've pressurized the whole cooling system to 16psi, more than double the systems 7 psi while operating. I also did that with the heater core open so I can't imagine air would have had any place to hide or be trapped.

[Clifton]

Clifton do you really think that there could still be air in the system? I've pressurized the whole cooling system to 16psi, more than double the systems 7 psi while operating. I also did that with the heater core open so I can't imagine air would have had any place to hide or be trapped.

You don't have any HG symptom but the coolant color tests do work if combustion gas enters the coolant. I've used them.

It's not the pressure, any small air pocket will prevent water flowing. I went crazy always burping and trying to get air out of the top line. Until I could get it all out, it would not flow well. It's not just a Europa thing. A lot of mid engine cars.

I don't have a Europa radiator but my radiator top bleed line Tee's in with the outlet on the top of the radiator hose high spot and then go back to my swirl pot. I haven't had to burp since.

Do you have an air bleed on your radiator? Have you checked it recently? Are you 100% sure there isn't a high spot that could have trapped air? Air will not travel back down to escape.

Pic of my setup and a fill kit.

[Clifton]

Just wanted to add. Being that you have removed your thermostat, you should have flow. Radiator in/out being the same temp means you don't. Another reason I think you have an air pocket.

[jbcollier]

There should be air bleed valves at the radiator and by the water pump.  Pressurizing does nothing to remove trapped air.