I am trying to figure out if IV got a bad headgasket. I have a 90 renix, fully converted to the open cooling system.

New parts as of February:

180* tstat
Waterpump
3 core brass radiator
Upper and lower hoses
Heater core is bypassed due to leak.
Newer universal overflow tank.

I do.not have money to rent a compression tester at the moment, I have read online to run the engine with the radiator cap off and while reving the engine if I see a bunch of bubbles coming up the filler neck then I am getting piston chamber gasses in the coolant. ( not sure if true) however I am getting bubbles when revving the engine up. Also after shut off my radiator continues to push the coolant out slowly. Any other easy ways to test if it a bad gasket until I can get some money to buy/rent the compelression gauges?

 

Have you checked what your local parts store charges to rent you a tester? It won't be much. Find a way to get one. The compression test is much better than any other way; it is absolutely the gold standard.

Good data = good decisions.

 

My wife works at harbor freight and I can buy one for like $15-20 do you think it will be accurate?

 

Bubbles can be from air pockets in the system too...it'll burp and bubble until all the air is worked out. At some point it should stop though.

Any other symptoms that point to a head gasket problem? Oil in the coolant or vice-versa?
Bad idle? Missing/misfiring? Overheating? White smoke from the exhaust? A steam-cleaned plug or two?


The harbor freight tool is probably fine, provided it is a screw-in type and not one with a rubber plug you have to hold in place.
Can you post a link?

 

I can get a link later from my computer I'm currently on my cell. The harbor freight one does screw into the head. I was just wondering about an accurate reading. Havnt checked all the plugs. Oil looks clean and no bubbles or anything like that in it.

I do believe i have a leaking freeze plug on back of block inside the bell housing. That leaks about a drop of oily coolant mixture every 10 seconds while engine is running.

The coolant kinda looks murky brownish red, my first thought was rust in the system but it was that color right after I swapped every cooling system part to the open system including new fluid.

The Jeep does run warm, after about 10 miles I'm running 220*. Once the engine is warm the idle gets rough sitting at a light and so forth. Cruiser54 has stated that a big problem is the leaking freeze plug because it is.not holding pressure I. The system.

 

I don't want to distract from these fine people. If you power/brake it (gas it in drive with your foot firmly on the brake), and see a notable difference in the bubbleing.....you get it. The higher combustion pressures would escape more with your foot in it. Be carefull of course, nobody in front of the jeep.

Also those gasses are nutty hot...a factor of 10, (coolant 200, combustion gas, 2000*). I don't think it takes much of a leak to drive the coolant temp up FAST.

 

If I saw a noticeable difference in.bubbles would you say the headgaskets toast? Cus if I Rev the engine in park to a very high idle the.bubbles increase.

 

May be I missed it but you didn't mention anything about what symptoms led you to all this? Does the motor overheat? Are you loosing coolant? What?

 

Usually I'd be doing that test cuz it was over heating. You overheating? What is the actual problem? Are you the guy with coolant dripping off the bell housing? Anyway, as stated you might want to do a compression test...I can't say I've done it but...power breaking with just a little throttle, then giving it a bunch more gas, if combostion gas is going into the water jacket, there will be more. I once had a nearly solid column hit the hood! (NOT a 4.0)

 

Quick recap.

February-

Converted 90 renix to open cooling system with the following:

Brand new water pump
New 3 core all metal radiator
All new hoses
Heater core is bypassed due to leak
New 180* thermostat
E fan is wired to a toggle constantly on.

I live in AZ ambient temp in summer where I live is about 105-118 in summer.

I am loosing coolant out I believe the rear freeze plug in block (not the head). The one inside of the bell housing.

My Jeep runs hot anytime I drive over 10 miles. Not extremely hot but in between the 210 and the.next line. IV got oil seapage out of the head gasket on the passenger side behind the distributer. I also have a bad exhaust manifold leak I need to address. I believe that is all the factors at the moment I have. Also Idk runs constanlty fluctuates when warm and is barely at 500rpms.

 

This is the best and most accurate way to check for exhaust in the coolant.


however I would recommend checking compression, and fixing the coolant leak before using the "air bubble" test as any kind of grounding evidence, as when things can leak out, things can leak in.

 

"oil seapage out of the head gasket" . To restate, (from your other thread), that IS a little odd, there is no oil under pressure there. If that really is the case, the compression test will probably point to head gasket trouble. Hopefully it's pissing coolant into your bell housing (which you might find with a rag), as well!

Sorry btw, I hate when that happens!

 

Well I can power wash my engine and use heavy degreasee and passenger side gets spotless. In about a day or two you can see where the headgasket is leaking own the block. I always assumed it was oil but I guess coolant could be the culprit.

 

I re-read again. The accuracy of the compression tester isn't so much the issue. Really the "pay dirt", is the relatave difference between the cyls. Your battery, starter, and the wires there will be a big player there anyway. Ideally, you'd have it warm, on a warm day, wright down all six, with 5 or more strokes. Then blast a couple tablespoons or oil in there, crank it to move that around. Then your second set of numbers will tell you things, like, "#5 came way up", must have been a ring/piston issue, not a valve or head gasket issue" ......I guess there is stuff on google and U tube..

If you are bubbling, getting hot right away, and seeing stuff leaking, (you might just clean there with soap and water). Gotta suspect that HG..

 

Yeah that's what I was thinking. If I have all these issues, what would doing the head gasket hurt? Other than it take time and patience to do I really wouldn't be loosing anything.in the end. The Jeep has 250k miles on it sso I would assume most engine with that kind of mileage need new gaskets.

Well I guess I will be doing the head gasket here soon and seeing how many leaks I can stop with that. For sure the head and bad exhaust leak, then the next step is dropping my tranny to get that freeze plug.


I am kicking myself in the *** because I had money set asside from my income tax check to have a rebuilt engine installed for $1800 out the door. Well I spent that money and now am dealing with the aftermath.