Cause of no compression CYL #6 3FE (2 Viewers)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Dec 9, 2019
Threads
32
Messages
174
Location
Frisco Co
Website
www.bighollowguitars.com
Hey all,
I was running a compression test on my 3FE and found pretty consistent numbers; cylinders 1-5 are within 5 psi of each other, right around 120 PSI. Adding oil bumped them up to 130 psi, so a little cylinder wear.
Cylinder 6 however isn’t pressurizing at all.
The funny thing is the truck runs fine. I took it out for some high altitude wheeling with the family last weekend, and averaged 13-14 mpg.
what is the next move now that the tester is showing no compression in cylinder 6?
Thanks so much.
Bevan
 
Hey all,
I was running a compression test on my 3FE and found pretty consistent numbers; cylinders 1-5 are within 5 psi of each other, right around 120 PSI. Adding oil bumped them up to 130 psi, so a little cylinder wear.
Cylinder 6 however isn’t pressurizing at all.
The funny thing is the truck runs fine. I took it out for some high altitude wheeling with the family last weekend, and averaged 13-14 mpg.
what is the next move now that the tester is showing no compression in cylinder 6?
Thanks so much.
Bevan
Do a leak-down test to determine if it's valves related or rings related.

Do a radiator compression test to see if it's HG related.
 
Sounds valve related
 
Haven’t adjusted the valves yet. Just getting the rig baselined after purchase. I don’t have a leak down tester, so I might just get a valve cover gasket and adjust the valves/check for any funny business.
 
I seriously doubt that the truck would be "running fine" on 5 cylinders. If there was really no compression on #6 she would have let you know.
I suspect that the compression tester was not seated correctly in #6.
 
Jon, thanks. That was my feeling too. I had already reattached the gauge twice but the third time was the charm. Got my last compression number: 120 psi in cylinder 6.
Good way to end the day.
 
Jon, thanks. That was my feeling too. I had already reattached the gauge twice but the third time was the charm. Got my last compression number: 120 psi in cylinder 6.
Good way to end the day.

@jonheld is smarter than your average bear. Figured he had it right as soon as I saw his post. #6 cylinder is a bit hard to reach and get it to seal correctly.

Good job guys!
 
Haven’t adjusted the valves yet. Just getting the rig baselined after purchase. I don’t have a leak down tester, so I might just get a valve cover gasket and adjust the valves/check for any funny business.
The 3FE wants a valve adjustment every 15K miles according to the factory service manual (FSM). Personally, I never did mine that often. However, if yours haven't been done in the last 30 years, they're more than a bit overdue. Have a look at this document. Individual parts are available from Toyota, and Wits End sells a complete kit using OEM parts.

 

Users who are viewing this thread

Back
Top Bottom