Back in December of 2025 I replaced the cracked block FE360 with a FE390.
Had a very reputable local machine shop do the all machine work and actually build the engine up into a long block
They even came by my house and helped on the initial start-up/cam break in and provided the use of a custom made oil pressurization bucket for the initial start-up.

I'm about 6 months and 1500 miles into this new engine and I've noticed some leaks.
Drivers side rear most freeze plug is leaking coolant and the intake manifold is leaking oil at the rear china wall - they used the cork gasket.

Looking for recommendations on what approach/attitude to take to the machine shop on Monday am and what I can/should reasonably expect..
My go to approach would normally be with my "Irish up" and "Guns Blazing" but I am willing to listen and adjust to what the collective brain trust recommends.
Thanks in advance
Tbruz

 

Hey
First off, this is lousy news and I truly feel bad for you and the machine shop. Having just rebuilt my 360 I can tell you (and you already know) that prep is everything. I don't think there is really anything wrong with the parts they've used (I used cork china wall gasket too) but I did use aviation seal on both sides of the cork plus Ford RTV at the coolant ports, at the unions of the intake/head/block. I meticulously cleaned the freeze plug holes and installed the new plugs with clear RTV as suggested by Lykins Motorsports. So, back to what do you do... it sounds like the machine shop wanted the best for this rebuild and also sounds like they went the extra mile (oil pressurization bucket, helped with cam breakin etc).. I think I'd be going back to them and explain your disappointment with what's happened. I'd give them the chance to make this right. Hopefully they do.

I can say that for my paying customers who I do car repair for, the ones I want to help most are the level-headed folks who don't approach me guns-ablazin. I don't have that many comebacks or problems, but when I do, I think it's better when we all agree the outcome isn't what was wanted or expected. The honest shops want to make stuff right. IF they don't you amp up your complaint. Fingers crossed you don't get to that.

Keep us posted!

 

This is why I like to do my own engines. and if I do screw up it's my fault so there's no worrying about who's going to fix it.

Those are not big problems, and some of what they're probably going to say will depend on how bad it is. if it's minor, you'll probably be on your own. if it's bad, they should fix it, in my opinion anyway. but it won't surprise me if they won't.

If you weren't around when this vintage of vehicle was new it helps to know leaks were just part of the experience. there was a reason they only had a 12-month 12,000-mile warranty.

 

You could try some Barrs leak for the coolant. Sealed up a littleleak in my alum rad with no other eeffect.

 

I did end up sending the machine shop the following text:

"...wanted to advise you that my FE390 engine has developed a freeze plug leak in addition to the ongoing manifold oil leak I previously told you about.
Wanted to give you a heads up so we can discuss this on Monday and hopefully work out some resolution"

Will advise as this unfolds......
Tbruz

 

Old saying....catch more flies with honey than vinigar or even than with guns a blazin. if you go in with guns a blazing I am sure you will get you no where fast. What kind of warrenty did it come with?

If the shop came to you YOUR location for the cam break in, they sound like a straight up fair shop. So give them the oppertunity to make it right. 6 months and 1500 miles I would think you should not have any leaks. Good luck with getting it resolved.

 

Tough situation for sure. Since it seems they went out of their way for the break in at your house, I would just fix it myself. I don’t know how I would even approach letting them know of the leeks I was fixing, but they should probably know, especially if there is a larger problem getting ready to rear its ugly head. I wouldn’t want to ruin the warranty because I worked on it last.

Approaching it like that would be far from guns a blazing. They would probably say they would rather fix it.

 

Just got back from the machine shop. They were very accommodating and immediately stopped what they were doing to look at the engine.
They confirmed both leaks and attempted to set/tap the leaking freeze plug in a bit deeper and gave a snug up on the valve cover bolts.
Will drive around a bit and see if that resolves the issues.

They stated that during reassembly they were extremely liberal with RTV on both sides of the China wall cork gasket so they suspect the valve cover gaskets first.
They also installed a leak trace dye into the oil so we can determine if its the back of the valve cover or the actual China wall.

More to come I suspect...
Tbruz

 

great news... yea trace dye is a really good tool to help identify where the oil stems from. Glad they were so responsive