So I tested the cylinders on my jeep today (4 front cylinders because it began to pour down rain) and they read 110 psi plus or minus 4 psi. I did not have the engine hot and I couldn't get the reader tight on the adapter. If all of the cylinders read in this 110 range, could I deem the engine fine? Also, the engine has 179,xxx miles on it, though Im not entirely sure the reading is accurate.

 

1. If you have 6 cylinders and you test only 4 of them, then you have more work to do. Test ALL cylinders.

2. Why are you testing compression? Are you having problems? If so, provide details so we can try to help.....

 

Ok, have a bit to fill you in on.
So on a drive to the obx the engine overheated several times. Turned out there was less oil in the engine than there should be. A lot less. lesson learned. Put in oil, went on. A couple days later, overheated again. This time, I checked the oil and there was plenty in it, but the oil pressure was low. Ran back home with about 10 gallons of coolant in the trunk stopping periodically to cool down. First thing I replace is the oil pump because no oil pressure is not good (duh) and would definitely cause the engine to heat up. After doing this, it helps, but its still getting hot, and in addition, there is some smoke coming from the pipe at idle when it gets to 210 ish. So before I go tearing into the head replacing rings and gaskets and whatnot, I'm checking the compression to see if anything is abnormal, bringing me to our current situation. Long story short, Hot engine, bit of smoke, pretty old engine, leading me to a compression check.

Also, like I said, I could only get to 4 Cylinders because it began to pour its butt off and blow hard, resulting in my tool box falling over and scattering sockets and wrenches EVERYWHERE.

I did get to the last 2 cylinders and did 2 things differently.
1) I took a set of vice grips and lightly spun the line tight to the fitting
2) Instead of turning the throttle body by hand to open it up, I pushed the accelerator pedal down.

The results on these 2 cylinders were 122 and 124 psi, which is in that 120-150 range.

Tomorrow, I am going to try the same thing with the other 4 cylinders and see if there is a difference. Also, how much of a difference is there if you take out all of the spark plugs?

If you think there is a better approach to the situation PLEASE let me know as this is my first project car and Im still learning what there is to know.

 

1. Stop using vice grips.
2. It only needs to be snug.
3. Pedal or open throttle by hand - no difference.
4. Your oil problem did not cause your overheating. More likely the other way around.
5. Find the source of the overheating and fix it, assuming the compression tests okay.
6. Even if the compression is okay, the engine might be shot due to worn bearings, a very normal cause of low oil pressure. (Oil pumps usually fail catastrophically, not gradually. Meaning, you suddenly have nothing. Replacing the pump was probably a waste of money & effort.)
7. Stop using vice grips.
8. Test your oil condition, including testing for coolant in your oil.
9. Test for exhaust gasses in your coolant.
10. Stop using vice grips.

Oh, and stop using vice grips.

 

Okie Dokie then
I would think that having low oil pressure would cause moving parts to heat up. Also, replacing the oil pump was, quite on the contrary, not a waste. My oil pressure increased from 0 to 20 at idle and 40+ on the road. Checked bearings with oil pan off, looked fair. Can safely say that there is no coolant in the oil. How do you test for exhaust gasses in coolant? And could a painted rad affect its functionality?
Thank you for your relpy.

 

Not really. It's not always visible. A Blackstone test will tell you a LOT more than just about coolant. Given your engine's history, you need that information.

See the link I posted.

If you mean any paint other than what it came with, YES!!!! That's a huge no-no.

 

OK, ill look into those tests. Seem expensive but worth it. Should have asked this question before, but does it mean anything that the engine runs decent? Yes it did overheat on a trip, but it doesn't knock, idles fine, doesn't shake, and keeps pretty good mpg. I would think that an engine that is about to go would have bigger problems than overheating. I do thank you for your time. Hate playing 20 questions but i would rather ask than not.

 

Questions are good. Ask!

The only time 20 Questions is a problem is when the OP makes us play 20 Questions just to get basic info about the problem he's trying to solve. You aren't doing that!


No, you could have shot bearings and weak rings and it would run fine. These motors are pretty tough! Your compression numbers are cause for concern, which is why I suggested the Blackstone test.

Something else to consider - the MMM Treatment. Not expensive, often works (if the problem is just gunked up rings), and worth a shot.

Pull the spark plugs, grab a funnel and pour a few ounces of Marvel Mystery Oil into each cylinder, and let it sit that way overnight. Use enough that it will saturate all the rings all the way around. Cover the plug holes with rags. In the morning, with the spark plugs still removed (and the plug wires kept away from any grounds), turn the engine over enough to blow the MMM out of the cylinders. It's messy, hence the rags. Reinstall plugs, and fire it up. It may smoke a bit as the oil in the cylinders is burned off. Re-check compression.

 

Sounds like a plan to me!
Took the truck out today and found some interesting stuff.
The engine never overheats while its running, but rather when it is stopped and turned off. If I let it idle and cool down it is fine but if I just take the key out, Coolant comes out from the overflow tank. With the key in and the engine off, I watched the temp needle rise to the 3/4 mark (can't remember the number off of the top of my head). This thing has me puzzled, but I ordered the testing kit from blackstone and I am definitely going to give the MMM treatment a try. Hopefully I can find something In these tests.

Again, thanks for the tips.

Would you mind if i added you to my friends list?

 

[QUOTE=Cherokoolguy;3390513]Sounds like a plan to me!
Took the truck out today and found some interesting stuff.
The engine never overheats while its running, but rather when it is stopped and turned off. If I let it idle and cool down it is fine but if I just take the key out, Coolant comes out from the overflow tank. With the key in and the engine off, I watched the temp needle rise to the 3/4 mark (can't remember the number off of the top of my head). QUOTE]



Bad or wrong radiator cap? Mine was doing that, not overheating according to temperature gauge but spilling out the overflow tank. I noticed the cap was 13# which is spec for the closed cooling system, mine was converted to open by PO and spec calls for a 16# cap. Fixed.

 

[QUOTE=pvsprme;3390716]Ill try that. I was just going to go ahead and replace all of the cooling components. Hoses, radiator, thermostat, thermostat housing, fan, fan clutch, fan shroud, water pump, heater core, and transmission cooler. And a cap of course.