Coolant Leaking Out of Manifold Joint and Eating Spark Plugs in Cylinder One

My '95 (2.7L) has several problems or one big inter-related problem that may finally be shaking out after a year of looking for the reason. I'd never heard of a forum for help with my truck before so I'm hoping you all have some insights. I do my own basic maintenance but I've got no manual so its a lot of question asking and research to yield successful major problem wrenching. The engine is eating the spark plug in cylinder 1 every 3-5 months; its been leaking coolant for a while but not from any obvious place and randomly the "check engine" light would come on, stay for a drive or four and then go off (this has happened about 6 times over the last year). No error codes were detected by the reader from the light being on.

Addressing the issues: first the check engine sensor and spark plug - I have replaced the spark plug 3 times over the last year. The truck runs rough when it starts and then smooths out after about 5 minutes and runs fine for the rest of the day with a small miss from time to time. The truck runs in this manner until there is a sudden lunging of the engine, the check engine light goes on and there is no power. I check the gap on the #1 spark plug and it has become so large it can no longer work. A new spark plug makes it all run fine for several months (with the possible slight miss still felt). I've checked timing, spark plug wires and finally had a mechanic look at the problem with no success. Finally last week the check engine light came on again but it said the first bank O2 sensor had failed. I changed it and figured that would account for the eating of the spark plug. And hoped all would be fine. But no.

Unfortunately when I was changing out the sensor (at 1 am) I noticed coolant dripping out of the joint btwn the manifold and the exhaust pipe (before the cat). Maybe this explains why when searching for the leak and finding a small pin prick in a hose, changing the hose did not fix the leak. I need to put water/coolant into the radiator once every 8 days or after long trips.

When I replaced the sensor I also checked the spark plug and the gap was again huge. So I've put in a new spark plug. But this time the missing is very noticeable and I'm not all that comfortable driving it any where.

I want to figure out what is going on. Is the undetected leaking and the spark plug destruction related? Maybe a new head gasket? Is there a way to determine if the coolant is leaking into the #1 cylinder? Is it fixable? Is the problem something else all together? Does anybody have any ideas or insights? Questions?

There are about 247K miles on the truck now.

Thanks.

K

 

there is a test kit that checks for exhaust gas in your coolant. remove radiator cap start engine and if the head gasket is leaking, the fluid in the test kit changes color. you can buy them on ebay

 

I would suggest you pm chris4x4. he has a lot of knowledge on mechanical stuff here , good luck

 

With the things that you are describing, I agree that you are looking at an internal problem. The coolant in the exhaust is indicative of a leak of some kind, either a blown head gasket, or something worse. The best advice I can give is like mentioned, consider using a tester to check for exhaust gasses in the coolant. Also I would run a compression test on all 4 cylinders and look to see if #1 is low, or excessively high. (A high compression could indicate coolant leaking into the cylinder) The coolant in your exhaust stream is most likely the reason for a failed O2 sensor, as these sensors do NOT like coolant. If the CEL is on, there should always be a code stored. If not, then you may be looking at additional problems. Let us know what you find out. I will be happy to help the best that I can.

 

Thanks for the advice. I'll try to run the tests this weekend.
By the by, while I was out finding a manual and borrowing the tools for compression test etc. some bleepity bleep stole my catalytic converter out of my drive way last night.

There has got to be a way to regulate the recycling of these things so that people stop stealing them. This is the 10th one I've heard about in the last 2 yrs from friends and local business'. Its a pisser!

I guess I'll have to add that to the late night wrenching schedule.