Engine 5.0 Head Gaskets installed wrong block coolant passages???

Xam Sirrah · Jul 21, 2025

Hi all, I’ve been chasing heat problems for a while now. About 9 months ago I swapped gt-40s and a cobra manifold onto my 5.0 with an Anderson cam. The problem arose after this swap. When the car heat soaks coolant temps can get all the way to 220f, and Intake Air Temps up to 180f. I have a frostbite radiator that is good for like 600 hp so I don’t think that is the problem. I have also been chasing weird coolant leaks at the timing cover area during this time. I recently saw an engine masters episode where Steve Brule of Westech said if SBF head gaskets are installed on the wrong side that they will block coolant passages. Is this true?? I did H/C/I on a previous car and had no issues.

Hoping someone with a little more experience can weigh in here?

Thanks

Max

Noobz347 · Jul 21, 2025

Somebody else can chime in here but I don't think left or right matters. What matters is front to back and are easy to install backward.

Mcmahst · Jul 21, 2025

When you installed the head gaskets, did you see “Front” stamped into the gasket. If not, they’re likely on backwards.

General karthief · Jul 21, 2025

IIRC there is a quick way to tell that has to do with a tab.......let me look around......

General karthief · Jul 21, 2025

Found it:

Thread 'Head gaskets installed backwards???'

Nov 13, 2005

What would the symptoms be if the head gasket's water ports did not line up right (the front was towards the back)? I mean I know that this would compromise the flow of the coolant but how hot would it run? Has anyone had this happen to them? I'm not an expert in this area but my car runs too hot since my HCI and I have changed everything and even in cooler air the car runs close to 200. I'm pulling my hair out trying to keep this thing cool and am wondering if I installed the gasket wrong. I would hate to go through all the hassle of pulling a head just to see if it's right. Thanks

Most of the thread (it is a few years old) are theories but one post confirmed the tab sticking out between the front edge of the head where it meets the block.
The only time I witnessed the symptoms when this happened it overheated massively in a matter of minutes.

Mcmahst · Jul 21, 2025

I wonder if you might have an air pocket? Some folks drill a small hole in the thermostat to evacuate the air. Just a thought.

Xam Sirrah · Jul 22, 2025

Mcmahst said:
I wonder if you might have an air pocket? Some folks drill a small hole in the thermostat to evacuate the air. Just a thought.

I have had that thought as well. Have burped the coolant system several times while parked on an incline.

Xam Sirrah · Jul 22, 2025

Mcmahst said:
When you installed the head gaskets, did you see “Front” stamped into the gasket. If not, they’re likely on backwards.

General karthief said:
Found it:

Thread 'Head gaskets installed backwards???'

Nov 13, 2005

What would the symptoms be if the head gasket's water ports did not line up right (the front was towards the back)? I mean I know that this would compromise the flow of the coolant but how hot would it run? Has anyone had this happen to them? I'm not an expert in this area but my car runs too hot since my HCI and I have changed everything and even in cooler air the car runs close to 200. I'm pulling my hair out trying to keep this thing cool and am wondering if I installed the gasket wrong. I would hate to go through all the hassle of pulling a head just to see if it's right. Thanks

HoofnIt

Replies: 20

Forum: 1994 - 1995 Specific Tech

Most of the thread (it is a few years old) are theories but one post confirmed the tab sticking out between the front edge of the head where it meets the block.
The only time I witnessed the symptoms when this happened it overheated massively in a matter of minutes.

Thank you! I just went out and checked and the tabs are in front. I don’t realize there were those tabs. Just checked on a couple new gaskets I have sitting around and it seems that they are installed the right way. So the problem must be stemming from something else. I’ve got a 3000 rpm converter on the car with the fluid being cooled by the radiator as well as an external cooler. But that cooler is right in front of the radiator so must be just heat soaking. Idk

General karthief · Jul 22, 2025

Is it overheating like spew'n steam or just hotter than in the past?
When you say 'heat soak' what do you mean, engine running or not?
And I never run the trans cooler through the radiator, duel plate coolers in front of the radiator would be my choice, only advantage to running cooler line inside the radiator would be for fast warm up on a freezing day, but it's been done for eternity
When I 'burp' a radiator I make sure the top of the radiator is highest point in the cooling system, fill, squeeze the lower hose many times, running the engine up to temp and leaving it overnight, make sure the puke tank has enough fluid and monitor engine temp with a mechanical gauge, the factory gauge is just a teaser.
Written by an 'old guy' after too much coffie

limp · Jul 23, 2025

General karthief said:
Written by an 'old guy' after too much coffie

coffee Geezer day this thursday at Mitchells...... You can meet Bentley's replacement, Cue...

limp · Jul 23, 2025

General karthief said:
squeeze the lower hose many times,

Watch those fan blades when doing this... DAMHIK.....

AeroCoupe · Jul 23, 2025

1/8” hole in thermostat here:

Post in thread 'Snow - 93 GT Vert. Some battery woes'
https://stangnet.com/mustang-forums/threads/snow-93-gt-vert-some-battery-woes.906418/post-9386653

Qtrhrse23 · Dec 22, 2025

If they are backwards (HGs), you will know. Instant blown hg if you do. ASK me how I know. Installed my first HG in 2000. AND My second one the next day. Note, SBF or GM LS make sure coolant passages in HG are on backside of block. A mistake someone will do only once, if you learn from your mistakes. I try to learn from others mistakes too. Learn from mine.

Engine 5.0 Head Gaskets installed wrong block coolant passages???

Xam Sirrah

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Noobz347

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Mcmahst

General karthief

wonder how much it would cost to ship you a pair

General karthief

wonder how much it would cost to ship you a pair

Thread 'Head gaskets installed backwards???'

Mcmahst

Xam Sirrah

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Xam Sirrah

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Thread 'Head gaskets installed backwards???'

General karthief

wonder how much it would cost to ship you a pair

limp

wrap a little cheese around it and its a done

limp

wrap a little cheese around it and its a done

AeroCoupe

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

Qtrhrse23

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Engine 5.0 Head Gaskets installed wrong block coolant passages???

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Stangnet Facilities Maint Tech... Er... Janitor

wonder how much it would cost to ship you a pair

wonder how much it would cost to ship you a pair

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Member

wonder how much it would cost to ship you a pair

wrap a little cheese around it and its a done

wrap a little cheese around it and its a done

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

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