Coolant leak from rear of engine :(

[DrCharles]

I think I bought the wrong truck... ('93 F-250 7.3 IDI)... there is a significant (drip but not pouring) coolant leak at the back of the engine somewhere. Can't prove the previous owner knew about it either, and when buying a used vehicle from a private party it's caveat emptor anyway. Rarely do I get burned though. Shoulda paid more attention to the low radiator level... oh well.

Anyway, I am concerned that it's a freeze plug behind the flywheel. I cannot feel anything wet on the rear of the heads or at the head/block line. It only drips noticeably when warm and the engine is running. Seems to be getting on the y-pipe. Pulling the trans will really be fun on a 4x4, too.

Any words of wisdom?
thanks
Charles

 

[snicklas]

Is it dripping out of the access plate on the bell housing, or is it dripping off the engine?

If its coming out of the bell housing, it could be the one of the freeze plugs on the back of the engine.

If its coming off the block, it could be the block heater, which is behind the starter on the the passenger side. Or, I also had the heater hose on the barb on the passenger side head leak, run down the head and drip off by the starter.

 

[DrCharles]

On closer inspection it does seem to be coming down the block - but on the driver's side. There is some on the oil pan too. Hard to tell until I (or a local shop) cleans it all off and looks with a bright light. I think the shop with the lift will be worth the 1/2 or 1 hr to diagnose this in wintertime.

That huge fan moves a lot of air that blows drips around. Also the wind traveling through the engine compartment. And I did have the front up on ramps for a while today, changing the very gross looking oil in the ZF-5 and BW1356.

Some possibilities I'm thinking of:
Good - an accessible freeze plug on the side of the block
Fair - oil cooler o-rings, not too hard to repair
Terrible - head gasket, cracked head, cracked block...

 

[Thewespaul]

Honestly oil cooler is easier to replace than a freeze plug imo, that’s where I would check first.

 

[icanfixall]

Leaks on the drivers side usually are the oil cooler to block gaskets or worst case.the oil cooler headers are eaten away.Are you running coolant? Time to look closer for the source of the leak. Could be one of 3 freeze plugs on the drivers side of the engine or maybe the water pump too. That leak can travel too.

 

[DrCharles]

What do you mean by, "are you running coolant"?

It's filled with 50/50 Fleet Charge SCA and distilled water.
It's not running out in a stream, but a steady drip on the ground while the engine's running and it's warmed up.

 

[IDIBRONCO]

I'd check the oil cooler too. A cracked block is almost not an issue, especially on the driver's side.

 

[laserjock]

Check the oil cooler for sure. Could possibly be head gasket too but that’s less likely.

 

[icanfixall]

Thanks for answering about the coolant. When I mentioned this usually I ask when a member has freeze plug leaks. Many times freeze -plugs leak because no coolant is used and ONLY water is used...

 

[DrCharles]

Well, the verdict on the truck is in and it's crappy. Not one, but both head gaskets are leaking coolant to the outside! 13 hrs labor on the books. Parts won't be much, but even so.

If I could prove the guy who sold me the truck knew about this and hid it, since there was no evidence on a good test drive (and I looked underneath!), he would be getting served papers right now.


So I have a choice - do it myself this winter, or bend over and pay. It's still the truck I wanted, but not such a decent deal any more...

I found a local garage that wants $650 for labor, plus checking/resurfacing (minimally if needed) at a machine shop, plus gaskets. They've done them before and warranty their work. About $1200 (ouch) all in. They can get to it next week. I really don't want to do this in the driveway (or unheated dirt floor barn) in the wintertime. OTOH, four figure checks hurt also...

 

[vegas39]

That sucks, sorry to hear that.
I've done head gaskets on two trucks out in the driveway and it is a pain. Those heads are very heavy. Most guys prefer to pull the engine but I found it easier to do with the engine still installed.
If I had to do it again, I'd pay someone else now.
Make sure the oil cooler gets new o rings also, this is the perfect time to do it.

 

[Macrobb]

I've replaced head gaskets a couple of times, both in and out of the vehicle. It's a pain, but if you have the tools not too big a deal.
Head gaskets are around $50 each, plus a valley pan gasket and exhaust manifold gaskets...

BTW, don't feel bad... my '93(in avatar) is almost to that point; it's weeped coolant from the gaskets(on both sides) since last February when I basically overheated it.
It's not leaking much, though(a few drips when under heavy load), so I'm keeping an eye on the coolant and waiting...

 

[tbrumm]

If the head gaskets are not leaking much, and you do want to tackle the replacement of them yourself but when the weather gets warm, consider using a coolant system sealer like Irontite (blue and white bottle iirc.) I know this stuff will seal weeping head gaskets as I used it on my truck before I replaced the head gaskets. Irontite seems to be pretty well regarded and is not "snake oil". This may allow you to continue to use the truck for a while, get to know it, and make sure that this is the truck you wish spend the big money on. It could also buy you some time to acquire the parts, tools and the research time to undertake the project yourself. If you leave the engine in the truck, you MUST have a cherry picker to get those those very heavy heads off and back on again without damaging anything - including yourself. You will also need a good torque wrench. Some will say head studs are overkill, but if you are going that far in and doing that much work, the added expense of head studs is not that bad when you consider the overall cost of the project. As vegas39 mentions above, when the heads are off, it is super easy to R & R the oil cooler, so that is a must do! I don't think the prices the shop is quoting you are out of line at all-but I understand the cost is still painful. Here is a link to the thread I did on my head gasket replacement. https://www.oilburners.net/threads/7-3-head-gasket-replacement-arp-head-stud-install.76304/

 

[IDIBRONCO]

Remember, you may not be able to install head studs with the engine in the truck. You would be able to get most of them installed, but there could be clearance issues with some of the back ones. You would DEFINITELY have to remove the heater box on the passenger's side, and even then you may not be able to get them all installed. If you're going to do head studs, than I say save yourself a lot of headache and just pull the engine out. You'll be able to install the studs, the oil cooler will be even easier to remove, and you stand less of a chance of damaging head gaskets, cherry picker or no. Also, while cleaning out the threads in the block before installing the studs, I was hitting the oil cooler with a standard tap handle. I also had contact with the injector pump gear cover and the tap handle. One last thing, the engine really isn't as hard to pull out as some people make it. You don't have to disassemble any part of the body of the truck to do it other than the hood of course
.

 

[tbrumm]

Remember, you may not be able to install head studs with the engine in the truck. You would be able to get most of them installed, but there could be clearance issues with some of the back ones.

Good point! I was able to install the studs on my truck, but the ones closest to the firewall must be put in the head before the head is set on the block. Just hold them up in the head with rubber bands or cable ties when setting the head on the block. I had no issues with the getting the torque wrench on nuts afterwards to torque them down. The heater/AC plenum in the engine compartment will probably need to come out though.