When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I just installed a long block 400 in a 1977 F150 and everything is running good but I have an oil leak. It’s behind the alternator somewhere below the head on the passenger side. Only leaks when engine is running. I noticed on the old block that I had in the shop there is a small plug that appears to be below the thermostat housing area in a corner. Can anyone tell me if that plug (if bad) would cause an oil leak? Also is it threaded or what type of plug is it? I need to pull off the alternator but I thought I’d ask here since I can’t get to it till tomorrow. Thanks in advance.
Ok after more research I think it’s a dipstick opening for 2wd trucks and cars. That would for sure leak if it wasn’t plugged properly. Still trying to figure out what type of plug it is or the best way to seal it if it is the source of the leak. #1 in the attached pic that I found online.
Try a spent 9mm casing. If you can get an actual measurment off of it, adjust as needed. .32 is slightly smaller at 7.65mm, or .40 at 10mm.
You have those laying around the house or littering the street in front of the house, right?
Or, if you can get an actual measurement, visit your neighborhood big store and search for plugs in the Dorman or other fine brand bins.
Thanks! I probably have some brass laying around . I’m just hoping that’s where the leak is. If it’s not there I can’t figure out where else is would be leaking. It’s an ATK long block so they installed this particular plug but I found another one missing so it wouldn’t surprise me if this one is not correct.
On a good note she purrs like a kitten with the 255DEH cam, new valve springs, Edelbrock intake and 600 CFM carb. Got a good 20 minute break in at 2200 rpms. Hot oil pressure is 70 psi at 2200 and 40 psi at 700 rpm idle. Would have been batting 1.000 if not for the oil leak issue.
Turns out there was no plug in the hole that I suspected was the issue. Ended up using a short bolt and some RTV to plug it. I swear I looked the engine over and over when I thought I had everything buttoned up but I never saw that hole. My old engine was so gunked up that plug was completely obscured so I never noticed it on that one either.
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
. I’m just hoping that’s where the leak is. If it’s not there I can’t figure out where else is would be leaking. It’s an ATK long block so they installed this particular plug but I found another one missing so it wouldn’t surprise me if this one is not correct.
