95' K1500 Cylinder Drop

[364000K1500]

I have a 95' K1500 with 364,000 miles on it. Original everything. My first big problem started yesterday. One of my cylinders continues to fail. I put new spark plugs in a few days ago, and since then it continuously drops the same cylinder (2nd one back from front on passenger side). That particular plug seems to have some oil leaking out of the hole. I pulled the plug, wiped it off, put it back in....and it ran fine for 15 min. Then it dropped again. Then I replaced my PCV valve, tightened every bolt that I could find on the engine, and wiped the spark plug off yet again, and it ran fine for over 450 miles on the highway. Once I hit city driving again.....the cylinder dropped. What can I do? This truck has been in my family since it was brand new and I won't sell it. I'll do whatever it takes to fix it.

[maxwedge]

Welcome to AF. Sounds like oil is getting into the cylinder, bad rings, bad valve seals, leaking intake gaskets are all possibilities.

[tempfixit]

Which engine??
Do a compression check on all clyinders with a compression testing gauge, removing all plugs to do this is recommended. ( dry method) (Someone correct me if I am wrong on this but disconnect the fuel pump fuse or relay and run engine until it dies so you do not get fuel to the clyinders while doing the test.) Record compression for all clyinders.Once you know the compression on that clyinder use a squirting oil can and apply a couple of squirts of oil into the clyinder thru the spark plug hole and do another test. If the compression increases this usually indicates that the rings are weak on that piston.

This is the numbering sequence of the clyinders on a v6:
Drivers side starting with clyinder closest to radiator:
1, 3, 5
Passenger side starting with clyinder closest to radiator:
2, 4, 6

Numbering sequence for a v8:

Driver side starting with clyinder closest to radiator:
1, 3, 5, 7

Passenger side starting with clyinder closest to radiator:
2, 4, 6, 8

Post your compression results and hopefully we can pinpoint the problem better.

Hope this helps

[364000K1500]

Thanks for all the help guys. Its the 350 and by your numbers its cylinder number 4 that seems to be the problem. 2nd one back from the radiator on the passenger side. I would say all signs are pointing to oil getting in there. Bad rings...bad everything with 364,000 miles haha. Explain that compression check again so I can make sure I got it right. I know my way around most automotive stuff but this lower engine stuff is somewhat new to me. Thanks again.

[tempfixit]

Here is a site that shows different compression testers:

http://search.harborfreight.com/cpis...ster&Submit=Go

1- remove fuel pump fuse or fuel pump relay and runengine until it dies to get rid of any gas in engine.
2- remove all spark plugs
3- do a compression check on all clyinders by turning in the compression tester hose in spark plug hole and cranking engine over several revolutions and record reading for each.
4- if you have a low reading on a clyinder squirt some oil in that clyinder with a oil squirt can thru the spark plug hole to cover the top of the piston rings. If the compression reading is higher this normally means the piston rings are weak and faulty, or if you have two clyinders side by side that have low readings this will indicate a bad head gasket.

Post your compression reading and we will help pinpoint the problem.

AUtozone may have a compression tester in their Loan A Tool Program.

[364000K1500]

Hey thanks again for all this help. While I get started on this testing, answer me this....Why....if this is a leaky valve or gasket or whatever it is, would it start acting up, then run just fine for over 450 miles on the highway, then act up again once we got back into town?? any ideas?

[maxwedge]

Oil getting into a cylinder is more likely to burn off under the higher cylinder temps of high speed operation, around town the oil can foul the plug more easily.

[364000K1500]

Thanks for the info man. I appreciate it.

[364000K1500]

Another question.....with this cylinder out, will driving it cause more destruction? can i still drive the truck without killing everything else? is there anything i can do to temporarily fix things without paying all kinds of money to fix this? whats the cheapest way to fix it....a new piston ring or a new engine haha?

[tempfixit]

Originally Posted by 364000K1500

Another question.....with this cylinder out, will driving it cause more destruction? can i still drive the truck without killing everything else? is there anything i can do to temporarily fix things without paying all kinds of money to fix this? whats the cheapest way to fix it....a new piston ring or a new engine haha?

Have you done the compression test yet??

How much oil does it use (burn)??

You can still use the vehicle as is, depending what the problem is it could last for many miles as is or it could completely fail anytime. Just a chance you have to choose to take or not. Like I believe it was maxwedge said it could be any number of circumstances. The compression test will help narrow it down to the problem. Most likely it is either a bad piston ring that could be weak, stuck, or broken and if broken could severly damage clyinder wall beyond repair, or bad valve oil seal which would not be a expensive fix.

How much do you want to spend to fix and what shape is the rest of the vehicle in, how long do you want to drive?? The best senareo with a engine with that many miles would probably be find a used engine or a new Jasper or GM long block with a warranty.

Let us know the compression results.