4.0 OHV top end redo

[Dantheman1540]

Alright I’m 99% certain my 4.0 OHV has either cracked heads or bad gaskets. It overheats often and seems to be pressurizing the coolant system. Gonna do one final check tomorrow to know for certain but it’s pretty obvious. I’m stuck between two options in what to do.
1:redo the top end of the motor
2: TDI swap

leaning towards option one for simplicity and cost. However I’m not sure how I want to go about it. I’m assuming the heads are likely cracked and instead of pulling them and sending them to a machine shop I’d likely just buy reman heads and have them ready to go. I feel I could easily do the full head swap and everything involved in one weekend. I’ve done many LS heads and cams swaps in a day.

Question is what else should I do? The valvettain makes lots of noise but I really don’t want to dump lots of money into it. So is there a good affordable “get me another 20-50k mile” upgrade or parts set?

also anyone have a good lead on heads?

 

[Shran]

I'd just redo the heads. They are probably cracked. Machine shop I use says they rarely see good used 4.0 heads, they are all cracked somewhere.

These heads are brand new Ford parts, not reman junk or aftermarket who knows what. I have bought two sets, great quality:

Set of New 4.0L Ford Ranger Cylinder Heads 1990 - 1994 Casting Number 93TM 90TM | eBay

Casting # : 90TM6090BE, or 93TM6090AA.

www.ebay.com

Head gaskets:

More Information for ENGINETECH F244

Head bolts:

More Information for ENGINETECH HB122

 

[Dantheman1540]

I'd just redo the heads. They are probably cracked. Machine shop I use says they rarely see good used 4.0 heads, they are all cracked somewhere.

These heads are brand new Ford parts, not reman junk or aftermarket who knows what. I have bought two sets, great quality:

Set of New 4.0L Ford Ranger Cylinder Heads 1990 - 1994 Casting Number 93TM 90TM | eBay

Casting # : 90TM6090BE, or 93TM6090AA.

www.ebay.com

Head gaskets:

More Information for ENGINETECH F244

Head bolts:

More Information for ENGINETECH HB122

That’s a good price! I figured the heads are toasted this was a mostly mystery motor when I paid $500 for it and I did nearly no investigating so I’m not too upset. That’s actually a cheap rebuild right there.
Isn’t there an upgraded or replacement set of push rods or rockers that help with the oiling problem?

 

[rhekman]

eBay seems your best bet for heads nowadays. A few years ago I had two dead cylinders on bank 1 of my '95, and was able to buy a single reman head from AlliedMotorParts.com for $190 after core return. They now want $525 for a pair.

If you have valvetrain noise, you'll have to inspect what you've got, but I'd bet you can resolve most of the issues with new rocker arms and pushrods, then disassembling and cleaning your existing lifters.

New Melling rockers have larger oil holes, and there are youtube videos of how to take apart the lifters to un-gunkify them.

 

[Dantheman1540]

How’s my cart looking? I kinda didn’t realize all this stuff was so cheap.

 

[Dantheman1540]

Anyone think it’s worth finding 95tm heads for it?

I think that’s actually what it has now since it’s a 95 expo motor.

 

[Dantheman1540]

This is getting interesting, three tests I did and all three stayed blue. I then checked to make sure the thing works by sucking some air from the tailpipe and it definitely turned green. So I guess no exhaust fumes in the coolant

 

[Shran]

So are you losing coolant? How have you determined that it's actually overheating?

Lots of things in play here before you put heads on it. Thermostat working? Radiator plugged up somewhere? Cap in good shape, water pump functioning? No leaves & crap between the rad and AC condenser? Fan clutch working?

Is it getting hot at idle (ie, at a stop light) or when driving?

 

[Dantheman1540]

So are you losing coolant? How have you determined that it's actually overheating?

Lots of things in play here before you put heads on it. Thermostat working? Radiator plugged up somewhere? Cap in good shape, water pump functioning? No leaves & crap between the rad and AC condenser? Fan clutch working?

Is it getting hot at idle (ie, at a stop light) or when driving?

It can idle all day with the AC on blast and the gauge will stay at N on Normal. I can drive around town staying under 2k rpm and it will still stay at N in Normal. However as soon as I try to do sustained speeds of 55mph+ which is slightly over 2k rpm in 5th with 4.56/33”s. It begins to slowly warm up and after just a mile or so will sit in the middle of the gauge, then a few miles later it will creep towards M-A and if I keep it up it will push L on normal. If I slow down, or come to an idle it will recovery fairly quickly. Also if I turn the AC off it will climb much much slower and recover even faster. Just two days ago on my way home I smacked WOT in 1st gear just enough to slide around a corner close to my house that had sand washed over the asphalt. And then proceeded to keep it at wot through second gear. I’d say maybe a total of 10-12 seconds at WOT, and within a minute after it began to boil over out of the overflow tank. Previously I have given the truck much more WOT than that and it never got hot so quickly leading me to assume the problem is worsening.

Something I started doing last week was a radiator flush/clean. I drained it, added distilled water and then some prestone radiator flush, drove it for three days. Drained it, refilled with just distilled water, ran it for a minute or two, drained it again, refilled again, and I’m on my second bottle of the flush. Attached is a picture of what was coming out after the clean water flush after the first bottle of cleaner. Pretty rusty looking if you ask me, I did also see some small rust flakes coming out of the radiator which is on par to what I saw when I replaced the water pump, before this used motor was put in the truck.


The water pump is a year old, the radiator is a much larger all AL explorer radiator, it also has an AL shroud and a 14” Derale 1350CFM elec fan that is confirmed working. I even wired in a manual override switch so I can turn it on/off whenever I want. I did that so I could test if it was better to have it on or off at speeds. It appears to be pulling a considerable amount of air, although I suppose I could find a fan with higher cfm.

 

[superj]

if its doing it while moving, its not your fan cfm or anything like that. moving normally is hte radiator. you can clean it a few times but it might just need replacing.

if you pull the radiator, coca cola, or any cola, works good for cleaning the inside. lay the radiator flat and pour a couple of 1 liter sodas into it and let them bubble for awhile. rinse it out a few times and see if it helps.

maybe run the water hose through the upper hose and let it drain out the bottom, cleaning the block passages.

and also unhook the heater core and flush / reverse flush it a few times too.

after that, and after you test the thermostat, its the radiator.

 

[Dantheman1540]

if its doing it while moving, its not your fan cfm or anything like that. moving normally is hte radiator. you can clean it a few times but it might just need replacing.

if you pull the radiator, coca cola, or any cola, works good for cleaning the inside. lay the radiator flat and pour a couple of 1 liter sodas into it and let them bubble for awhile. rinse it out a few times and see if it helps.

maybe run the water hose through the upper hose and let it drain out the bottom, cleaning the block passages.

and also unhook the heater core and flush / reverse flush it a few times too.

after that, and after you test the thermostat, its the radiator.

That was my thought on the fan as well.

I guess I need to do some more flushing!

 

[Dantheman1540]

Might even throw a coolant filter at it.

 

[Shran]

I'd probably use vinegar before Coke but just my preference...

I think you need to do some more flushing. I put a different engine in my '94 recently and had a look inside the water jackets while I had the timing cover off... it was terrible in there. Big flakes of rust scale everywhere. Took a lot of flushing to get that cleaned up.

 

[Dantheman1540]

I'd probably use vinegar before Coke but just my preference...

I think you need to do some more flushing. I put a different engine in my '94 recently and had a look inside the water jackets while I had the timing cover off... it was terrible in there. Big flakes of rust scale everywhere. Took a lot of flushing to get that cleaned up.

you might be right, it was staying extra cool today and I did my best to give it lots of WOT and it never got passed the O. I’m draining it again now and my god it’s disgustingly orange

 

[Dantheman1540]

The result of flush 3 and flush 4. 3 is water with a cleaner and 4 is straight water and less than 5min run time. Doing the 5th now and prob 6th in the morning.