Coolant by-pass to OHV Intake manifold

[DPDISXR4Ti]

Over the years I've heard several cases of coolant leaks on the 4L at/into the intake manifold. I'm considering a 4L swap, but in the interest of plumbing simplification and reliability, I'd want to continue with a "dry" intake as is found on the earlier 2.9 engine. Surprisingly I can't find anywhere that this has been discussed. Is it possible? Has anyone actually done it?

 

[gaz]

DPDIS,

The 2.9 intake has the thermostat housing, both water temperature sensors and water passages in it; it's provides nearly the same exact functions as a 4.0's.

 

[RonD]

+1 ^^^

Can you post link to the "dry" intake, never read about it

The 4.0l OHV used an aluminum intake bolted to cast iron heads
IF..........you didn't change coolant then older coolant could cause electrolysis between the two different metals, this would eat away at the aluminum where it passed coolant to and from the heads, and you would get a leak
Front passenger side or rear drivers side where intake meets the head

This was ONLY an issue if you didn't change coolant for many many years, not a defect in design

 

[DPDISXR4Ti]

The 2.9 intake has the thermostat housing, both water temperature sensors and water passages in it; it's provides nearly the same exact functions as a 4.0's.

I guess I should actually study the 2.9 engine that's already in the vehicle before making assumptive comments on it! I've had the upper off the 2.9 several times but never bothered to notice that the lower is "wet". My bad....

But I wonder why we "never" hear about coolant leaks with the 2.9 intake but often with the 4.0? Is it maybe only the later plastic intake that was prone to failure due to plastic warpage?

 

[Snoranger]

The SOHC 4.0l has coolant leak issues with the plastic thermostat housing, the OHV 4.0l really doesn’t have a “known defect” like that. I’ve seen 200K mile OHVs that still had the original coolant.

 

[gaz]

DPDIS,

I may have a compromissed lower intake manifold gasket in my Ranger's 2.9 right now; no lack of irony, the engine sat unused for 15 years, which I believe is the primary contributing factor.

 

[DPDISXR4Ti]

The SOHC 4.0l has coolant leak issues with the plastic thermostat housing, the OHV 4.0l really doesn’t have a “known defect” like that. I’ve seen 200K mile OHVs that still had the original coolant.

Okay, perhaps I had heard about the issue with the OHC engine and mis-applied that to all Cologne 4.0 engines.

 

[DPDISXR4Ti]

I may have a compromissed lower intake manifold gasket in my Ranger's 2.9 right now; no lack of irony, the engine sat unused for 15 years, which I believe is the primary contributing factor.

Funny enough, one of the factors which got me considering a 4L swap was a very slow coolant leak which I've experienced on the 2.9. So it's possible I've got the same issue.

 

[gaz]

DPDIS,

Can you see where the coolant is leaking?

 

[DPDISXR4Ti]

Can you see where the coolant is leaking?

No, it's internal.

 

[SenorNoob]

The 4.0 OHV did have "revised" intake gasket set in I think '94. So there must have been some issue... I remember searching for one

 

[RonD]

No, it's internal.

Internal as in coolant in the oil
or
As in white smoke out the tail pipe

 

[DPDISXR4Ti]

Internal as in coolant in the oil
or
As in white smoke out the tail pipe

Neither, at least not obviously so. It is a very slow drop in coolant level, so no obvious evidence it really being left. In some ways, it would be better if it got worse so that I'd know what I'm dealing with. In the mean time, I'll research my options and patiently look for a 4L donor.

 

[RonD]

Put UV Dye in the coolant

 

[DPDISXR4Ti]

Put UV Dye in the coolant

That'll then show up in the oil?