1997 Explorer EGR

[JSmall]

What am I missing? My 97 has the external EGR but also has the hole in the intake. Is this normal? Do I need to block the hole in the intake?

Isn't this considered external EGR?

This is the upper intake.

This is the head

 

[Timmy390]

My upper intake is also a 97 Explorer and I blocked the hole with a steel freeze plug and high temp RTV. Don't recall the size but the local parts store had to "order" it.

I also plugged the lower with the same.

Tim

 

[JSmall]

I am curious what the hole does if I have an external EGR. That is my main question. I have late (GT40P) heads, external EGR, and an early upper and lower intake (RF-F67E-9425-CA) with the hole for the EGR.

Is it possible to do nothing with that hole due to the EGR/GT40P/intake combo that I have?

 

[hankjr]

I would think that leaving the hole open puts unnecessary pressure and/or heat up against the intake side of the intake. If you are using the external EGR, I would block at least the lower to keep the heat and pressure out of the upper.

My $0.02

Hank

 

[JSmall]

I would think that leaving the hole open puts unnecessary pressure and/or heat up against the intake side of the intake. If you are using the external EGR, I would block at least the lower to keep the heat and pressure out of the upper.

My $0.02

Hank

Where would that heat come from? I don't have the extra "hole" (not sure what it's called) in my GT40P head for the heat to pass through. "GT40 heads are equipped with thermactor holes to connect to the EGR/smog equipment"

Again, it is possible that I don't understand the system well enough to even speak to what I have :-[

 

[BroncoChicken]

I think the line you quoted answers your question. You have GT40P heads, your quote stated the GT40 heads have the thermactor holes. If you look at the first picture you posted, just below the computer plug, you can see the line that runs from the exhaust manifold up to the EGR valve. The exhaust enters the elbow there and runs through the center holes in your intakes. Are you going to run EGR? If not, tap and plug the holes in the intakes and remove the elbow from between the upper plenum and the throttle body.

*I think, but someone correct me if I’m wrong.

 

[JSmall]

I think the line you quoted answers your question. You have GT40P heads, your quote stated the GT40 heads have the thermactor holes. If you look at the first picture you posted, just below the computer plug, you can see the line that runs from the exhaust manifold up to the EGR valve. The exhaust enters the elbow there and runs through the center holes in your intakes. Are you going to run EGR? If not, tap and plug the holes in the intakes and remove the elbow from between the upper plenum and the throttle body.

*I think, but someone correct me if I’m wrong.

I'm not sure if that is accurate. I have always read that the internal EGR has GT40 heads and to block EGR the holes in upper and lower intake will need to be plugged. External EGR has GT40P heads and to block the EGR the 90* elbow is eliminated and the exhaust manifold is capped. Nothing internal needs to be altered on the external EGR. I am removing EGR and I have a combo of early (upper and lower intake) and late (external EGR and GT40P heads) parts.

*Edit* "GT40 heads are equipped with thermactor holes to connect to the EGR/smog equipment" would lead me to believe that the holes in the intakes would not need to be capped because I do not have the GT40 head with thermactor holes.

 

[hankjr]

I'm not sure if that is accurate. I have always read that the internal EGR has GT40 heads and to block EGR the holes in upper and lower intake will need to be plugged. External EGR has GT40P heads and to block the EGR the 90* elbow is eliminated and the exhaust manifold is capped. Nothing internal needs to be altered on the external EGR. I am removing EGR and I have a combo of early (upper and lower intake) and late (external EGR and GT40P heads) parts.

*Edit* "GT40 heads are equipped with thermactor holes to connect to the EGR/smog equipment" would lead me to believe that the holes in the intakes would not need to be capped because I do not have the GT40 head with thermactor holes.

good point. if the heads have the ports that line up with the internal EGR lower intake, there is the heat source. if not, then the holes simply go along for the ride so to speak.

Hank

 

[904Bronco]

Well from the looks of things in your pictures you have an early intake (96) with 97 EGR configuration with P heads. (looks like 4 hash marks on the head)

So you have internal EGR and External EGR ports??? Weird.

Since your wiring harness is configured for the external EGR, I think that would be the easiest for you to stay with. The 96 motor uses EGR that is internal and similar to 89-93 Mustang 5.0 set up (same EGR valve) with that 90* elbow. I am actually going to set up the 96 motor I have to run Mustang based EGR spacer and TB. (And eliminate the elbow) Been working with Garry EFI Guy on it...

I looked at the Felpro gaskets set for the Explorer intake manifold and the O'Reilly's site shows one set working from 1996-2001. So I am guessing if you pulled the lower manifold, you will not find the exhaust crossover blocked off.

I don't know what harm would come from leaving things the way there are? Considering how many miles are on this motor you have... But in my mind it is not right. The internal route should be blocked off, by either a pressed in plug or tap and thread the hole with a plug. The pictures I have of a later manifolds just eliminated the upper/lower ports.

It was just how your motor may have been assembled as it went down the line... emptying out production parts from 96 on a 97 build.

My .02 Doug

 

[904Bronco]

Where would that heat come from? I don't have the extra "hole" (not sure what it's called) in my GT40P head for the heat to pass through. "GT40 heads are equipped with thermactor holes to connect to the EGR/smog equipment"

Again, it is possible that I don't understand the system well enough to even speak to what I have :-[

There are no Thermactor holes in (bolt holes like a Mustang E7 head did) an Explorer GT40 head in 96 as they did not come equipped with a smog pump.

EGR system was fed exhaust gas internally in 96 and then externally (exhaust manifold to EGR valve) from that point forward.

I think the concern is that you have exhaust heat in the upper and lower plenums that is going no where.

By plugging the port on the lower plenum, you still have exhaust gases traveling through the lower intake crossover aiding with intake warm up. Later years eliminated this with the external EGR and then Ford provided engine coolant to recirculate in a portion of the upper plenum to assist with cool weather start up... See pic. Most people eliminated this when installing this motor in a Bronco.

 

[904Bronco]

Here are some of my random 96 Explorer manifold to Mustang based TB and EGR spacer.

You have to run a 70mm spacer and 65mm TB to be equivalent to the Explorer, with Explorer gaskets and some minor port machining to the Mustang EGR spacer to work.

 

[JSmall]

Well from the looks of things in your pictures you have an early intake (96) with 97 EGR configuration with P heads. (looks like 4 hash marks on the head)

So you have internal EGR and External EGR ports??? Weird.

Yep, that is exactly what I have. Very odd!

Since your wiring harness is configured for the external EGR, I think that would be the easiest for you to stay with. The 96 motor uses EGR that is internal and similar to 89-93 Mustang 5.0 set up (same EGR valve) with that 90* elbow. I am actually going to set up the 96 motor I have to run Mustang based EGR spacer and TB. (And eliminate the elbow) Been working with Garry EFI Guy on it...

I have already removed the EGR wiring from my harness so I'm guessing I should tape and plug the holes. Do I plug both upper and lower intakes?

I looked at the Felpro gaskets set for the Explorer intake manifold and the O'Reilly's site shows one set working from 1996-2001. So I am guessing if you pulled the lower manifold, you will not find the exhaust crossover blocked off.

I don't know what harm would come from leaving things the way there are? Considering how many miles are on this motor you have... But in my mind it is not right. The internal route should be blocked off, by either a pressed in plug or tap and thread the hole with a plug. The pictures I have of a later manifolds just eliminated the upper/lower ports.

It was just how your motor may have been assembled as it went down the line... emptying out production parts from 96 on a 97 build.

I am taking the engine down for a full rebuild so I'll look at the gasket. No harm in plugging the holes because I'm not sure if I'll keep the GT40P heads.

Thanks for the response! I figured you would set me straight.

 

[904Bronco]

I have already removed the EGR wiring from my harness so I'm guessing I should tape and plug the holes. Do I plug both upper and lower intakes?
Thanks for the response! I figured you would set me straight.

So definitely the bottom hole which is being fed from the heads.

So on the upper Plenum, can the EGR gases feed back from from the source at the Exhaust manifold? If so, Yes plug it.

 

[JSmall]

So definitely the bottom hole which is being fed from the heads.

So on the upper Plenum, can the EGR gases feed back from from the source at the Exhaust manifold? If so, Yes plug it.

Thanks! I'll plug the bottom hole. The exhaust manifolds are being replaced with headers so I should be good there. The 90* EGR elbow is being removed as well.