Engine Coolant leak from throttle body

91GTstroked · Oct 9, 2023

Hey everyone!

So here's the deal. I replaced the bbk 70mm TB and EGR spacer and went back to the stock TB and EGR spacer. I bought them off eBay.

I thought I cleaned them up well and used fel pro replacement gaskets.

It's leaking through the TB gasket. I can see a little puddle in the TB as well.

The car is a 90 7 up edition vert and motor is stock. So I don't really want to bypass the coolant passages on the EGR.

I've never had this problem with any other fox mustang that I've owned. People replace Throttle bodies all the time and I never hear about this.

Anyway, I ordered another set of gaskets . Can I use a light coating of "right stuff" rtv on the TB gasket that mates to EGR side?

I hope to work on this on Thursday.

Thanks!

General karthief · Oct 9, 2023

Yes. I use the blue Permatex on both gaskets on the EGR spacer side on used stuff. I also make sure both surfaces are flat.

91GTstroked · Oct 10, 2023

General karthief said:
Yes. I use the blue Permatex on both gaskets on the EGR spacer side on used stuff. I also make sure both surfaces are flat.

So to clarify, you also use it on the EGR to plenum gasket, but only on the EGR side? Basically, can I just put some on the mating surface on both sides of the EGR spacer, then put on gaskets?

I have some blue permatex thermostat housing rtv but I've never used it before.

General karthief · Oct 10, 2023

Yeah, I smear a thin coat on the gasket, stick it on and let it set for a few minutes with some weight to keep it pressed on, then do the other side of the spacer.
Inspect the spacer good for pits and cracks.
Normally I would say to block off or remove the lines to the spacer but it's kinda needed to cool the EGR gases entering the intake since this has a functioning emissions system (right?), I know you think 'cooling' with 190* liquid don't compute but the exhaust gases can be a few hundred degrees.
Disclaimer: info not based on any real mechanical training, use at your own risk!
Not many people or animals were harmed gathering this experience.

AeroCoupe · Oct 10, 2023

find a flat surface, get some 800 or 1000 grit sandpaper and check how flat the TB and spacers surfaces are. Don't mash them down or anything but with light pressure drag the TB and spacer across the sandpaper that is on the flat surface (glass works very nice) and see what king of pattern you get. Should have even contact across the entire surface.

91GTstroked · Oct 12, 2023

Update:

I just completed doing it over today. The EGR spacer definitely has a fair amount of pitting on the TB side. So I used permatex thermostat housing rtv on both gaskets that mate to the EGR sides. It's colder here right now, so I'm going to wait a few days before I start it up.

91GTstroked · Apr 26, 2024

Update:

Okay guys, it's still leaking. I've barely driven this car since going back to the stock setup.

I'm guessing the mating surface isn't straight. What are my options?

Can I try rtv only on both EGR sides? And what kind? My last attempt was gaskets with permatex grey thermostat housing rtv.

Or can I bypass the EGR coolant lines if I'm still running the EGR setup? Car is mostly stock.

slow84lx · Apr 27, 2024

That sucks!

Re-read post #5. Following this process can take care of the pitting and get the surfaces flat.

When it is apart check closely for cracks.

91GTstroked · Apr 27, 2024

slow84lx said:
That sucks!

Re-read post #5. Following this process can take care of the pitting and get the surfaces flat.

When it is apart check closely for cracks.

What do I do if it's warped? I may try permatex form-a-gasket lightly coated. The tacky stuff.

slow84lx · Apr 27, 2024

91GTstroked said:
What do I do if it's warped? I may try permatex form-a-gasket lightly coated. The tacky stuff.

If it isn't flat, sand it until it is flat. It won't take long and the pitting should be removed at the same time.

91GTstroked · Apr 27, 2024

slow84lx said:
If it isn't flat, sand it until it is flat. It won't take long and the pitting should be removed at the same time.

Thanks I plan on attacking this next week.

General karthief · Apr 27, 2024

It's leaking coolant right? It may be cracked, unhook the coolant lines from the spacer, blow the coolant out, spray brake clean into one nipple, a fair amount, look through the throttle body to see any wetness inside.
Make sure care is taken blowing out the coolant and blow it out again after you check for cracks and gasket misalignment.
DISCLAIMER: the procedure described may not be OSHA approved.

91GTstroked · Apr 27, 2024

General karthief said:
It's leaking coolant right? It may be cracked, unhook the coolant lines from the spacer, blow the coolant out, spray brake clean into one nipple, a fair amount, look through the throttle body to see any wetness inside.
Make sure care is taken blowing out the coolant and blow it out again after you check for cracks and gasket misalignment.
DISCLAIMER: the procedure described may not be OSHA approved.

Yes coolant. I will try this procedure. Maybe it is cracked. I bought both the tb and egr spacer used off eBay. Just sucks I had zero issues with the BBK setup, just wanted to put the car back to stock.

Engine Coolant leak from throttle body

91GTstroked

General karthief

wonder how much it would cost to ship you a pair

91GTstroked

General karthief

wonder how much it would cost to ship you a pair

AeroCoupe

lube between the nut and the face. I know my lubes

91GTstroked

91GTstroked

slow84lx

clean it good before insertion

91GTstroked

slow84lx

clean it good before insertion

91GTstroked

General karthief

wonder how much it would cost to ship you a pair

91GTstroked

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Engine Coolant leak from throttle body

wonder how much it would cost to ship you a pair

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lube between the nut and the face. I know my lubes

clean it good before insertion

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wonder how much it would cost to ship you a pair

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