I started a new account because I cannot find the info for the previous one. Anyhow, the other day as the tuck was idling I came around the corner to a puddle of coolant. Had to get to work so took the backup vehicle and had the IDI towed to the shop. They just told me the rig has bad head gasket(s).

Not sure if it is one or both because they didn't pull plugs but gas is getting into the system. No oil is found in the coolant or vice versa. There was some overheating issues about 100K miles ago due to a blocked radiator. At that time changed the radiator, fan clutch and added an extra temp gauge for the sake of redundancy and have not seen overheating issues since. There has been a bit of blowing white smoke but previous compression checks showed the gaskets were good. So this lead me to think the smoke was indicating the need to replace the injectors but once the glow plugs were changed the white smoke on startup diminished about 80% and white smoke on acceleration even diminished.

This is a great truck with a brand new rebuilt trans, new starter and several other replaced/maintained parts. I am not sure how much longer it will stay in the lineup but my preference would be to keep the rig as long as possible. My main issue right now is that I am having to pay a lot of money to people to help me keep it running and not sure which would be the best investment. The rig is over 264K and is a daily driver (all highway) and not seeing much towing lately. Also, the pump and injectors are OEM and looking to at least change the injectors on either a head gasket or rebuild. So the big question is do you do replace the gaskets, machine the heads and do the injectors or do you order a rebuilt engine and put on new injectors?

Any suggestions would be helpful.

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'94 F-250 XLT – Supercab, 7.3IDI, factory turbo, 4x4, 3”exhaust, newly rebuilt transmission, 264,000plus, high canopy with wood racks, newly re-powder coated 17"s - awesome rig

 

What was your compression when you tested before?

Also it's rare but it could be cylinder wall cavitation

 

That is a good question and I will look into getting that number. I did ask about cavitation but the shop did not suspect it. Monday I am going to tow it to another shop that has much more experience with internal engine work. They want to spend a bit more time on the diagnostics so we can get more information to work with.

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'94 F-250 XLT – Supercab, 7.3IDI, factory turbo, 4x4, 3”exhaust, newly rebuilt transmission, 264,000plus, high canopy with wood racks, newly re-powder coated 17"s - awesome rig

 

with blown head gaskets .. you often do not get coolant/oil mix as the heads on the IDI do not have oil passages .. the oil is supplied via the Push rods.

leaking coolant external is common when one fails.

 

Good point. Lost quite a bit of coolant out of the cap during idle. Thank you for the tip.

Forgot to mention I checked the coolant about 1-2 weeks before and it was fine.Then checked it the night before the issue and it was about 1/2 gal low. Refilled it that night and the next morning when it was idling the coolant was coming right out the cap. The cap was tested and it was good.

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'94 F-250 XLT – Supercab, 7.3IDI, factory turbo, 4x4, 3”exhaust, newly rebuilt transmission, 264,000plus, high canopy with wood racks, newly re-powder coated 17"s - awesome rig

 

s wondering what it meant if i have oil in my coolant could that be caused by a blow head or do i have a more sever problem going on

 

Most likely and cheapest fix as well would be bad oil cooler orings

 

When I had that problem couple years ago, I thought head gasket.
3 guys came back....Oil Cooler leaking.

Sure enough, that is what it was. It`s an easy fix, just a PITA job to get it done.
Then you have to clean the oil out of the cooling system.

Charlie

 

The design service life of the IDI between overhaul was 300k miles. You're almost there, it's due. I would do a full rebuild.

I was in a similar situation with my 6.9 a few years ago and tempted to do a quick and dirty head gasket replacement over the weekend but no parts were available locally so I got a 7.3 and built it proper with studs and some other goodies. https://www.ford-trucks.com/forums/1...hat-to-do.html

Your situation is similar with a "lesser" engine so to speak, because you have an IDIT crank and rods and as of a few years ago IDIT pistons are NLA. at nearly 300k miles your engine will need a bore job. I would be looking for oversize NOS IDIT pistons and failing that a parts engine for the crank and rods or to build. If you don't do that, bare minimum is pull the engine to do studs and head gaskets, guarantee it'll need valve guides, and I'd be concerned about taper on the bores with high miles but for a quick and dirty top end rebuild you might get away with a hone and rings.

 

If I ever rebuild a 7.3, I'd have it resleeved to standard bore so cavitation wouldn't be an issue instead of boring.

He could possibly then reuse his original pistons if they have acceptable wear.

 

I wouldn't worry much about the Crank, that can always be reworked .... rods as long as not bent or stretched should be fine, Mahale will make you a set of new pistons for a price, you might have a pretty long lead time too.

I would opt for a Ready to run replacement before doing a rebuild on an IDIT as it will most likely be less expensive ...BUT depends on how much money you want to spend.
either way I think IF it was me I would pull the engine and put it on a stand and at least go thru it before just slapping new gaskets on it... they are just a PIA to do an in frame on them.

and yeah IF I had to bore it I for sure would sleeve it...... whatever you choose you sure only want to do it 1 time.


BTW no problem getting new Pre-cups or replacement Guides ... I generally just buy the guides pre-knurled too.

 

Thank you, All. This is all great information to consider and thank you for leading me to the 6.9 head gasket post.

I got the rig to the other shop on Monday and missed a call from them today. So I am eager to hear what they say.

Based on the provided information I am leaning more towards sourcing a ready built engine should it come to that.

 

Got the report back from the new shop. They did a thorough review of the situation and found the radiator cap was bad! Amazing a $10 part compared to several thousand $$. They are showing 7.2psi and no gas in the system at idle, driving or towing. No coolant leaks of any kind. Their suspicion is the other shop was reading the air that got in the system with the bad cap and when the system was filled with the 1/2gal of coolant the night before.

Who knows. All I know is the new shop said injectors and head gaskets are good which would match what the previous compression tests showed. Thank you for all the support with this issue...now time to get it back on the road!

 

Nice! Glad to hear the ol dinosaur is okay

 

Wow, going from several $$$$K dollar engine rebuild to a $10 radiator cap.

I have an 82 Datsun 720 King Cab 5-spd with the Nissan SD-22 Diesel engine.
Bought it new in 10/81 for $7820.
I was some where past 300K miles when I thought the Radiator had finally
sprung a leak. Trying to find one new was next to impossible. Guy on the
Nissan forum had one in Medford, Or. doing a swap into a Jeep and no use
for the Radiator.

Driving down from Portland back to Ca. swung by and picked it up.
Get ready for the swap at home, and discover the 27yr old cap rubber gasket
had crapped out. Can you believe that? The cheap Japanese cap only lasted
27 years???

Replaced it and all was well and good.

See...it`s the little things that will get ya.


Charlie