Mishimoto Radiator leak 1987 Foxbody 5.0

PHoffman · Jan 16, 2025

I’m trying to find the leak on my mishimoto radiator or it could be a hose leak. Coolant is leaking but can’t tell where it’s coming from. I did notice a small leak from the overflow nipple so I just replaced the overflow nipple with a cap and clamp. This looks like it’s coming from the bottom. Any suggestions would be great. Thank you.

The pictures are from the left and the right side.

Noobz347 · Jan 16, 2025

Put this in with the coolant:

Auto Pro Antifreeze and Coolant Leak Detector UV Dye 1oz | AutoZone

Certified A/C Pro Engine Cooling Systems UV Dye is an engine coolant UV dye for leak detection. Includes one application of radiator/engine cooling system UV leak detection dye. Safe for use in all vehicle makes and models (except 1996 and newer GM models that use DEX-COOL coolant). Compatible...

www.autozone.com

Hose down the engine bay and let it dry.

Start the car and let it get to operating temp.

Shine a UV light into the nooks and crannies. Should stand out like a creep show.

PHoffman · Jan 17, 2025

Noobz347 said:
Put this in with the coolant:

Auto Pro Antifreeze and Coolant Leak Detector UV Dye 1oz | AutoZone

Certified A/C Pro Engine Cooling Systems UV Dye is an engine coolant UV dye for leak detection. Includes one application of radiator/engine cooling system UV leak detection dye. Safe for use in all vehicle makes and models (except 1996 and newer GM models that use DEX-COOL coolant). Compatible...

www.autozone.com

Hose down the engine bay and let it dry.

Start the car and let it get to operating temp.

Shine a UV light into the nooks and crannies. Should stand out like a creep show.

Thanks for the recommendation. I have one coming today. Hopefully I find that creep.

gkomo · Jan 17, 2025

I had a Mishimoto radiator in my old fox that developed a pinhole leak on the passenger side middle of the radiator end. Ended up replacing it with a Griffin radiator. Mine was obvious, i started 'steaming' while driving in traffic one day, pulled over and saw the steam shooting out of the pinhole. The above suggestion is good to identify the leak since you can't determine where its coming from.

PHoffman · Jan 17, 2025

Gotcha. I haven’t jacked the car up yet so I’m crawling under it and looking but can only see so much. I might just take the radiator out to see if I can find it. I did just check it and it’s leaking on both sides but can’t pinpoint where it’s coming from. I don’t think it’s coming from the top. I believe it’s coming from right underneath that black rubber piece? Please see pics on both sides. Is there a connecter or something loose under the rubber piece. Also coolant on the ground right under that rubber piece. Sorry no car expert but learning.

limp · Jan 17, 2025

Hook up a pressure tester to it.... If your taking it out, take it to a radiator shop and let them test it and give you an estimate for repair....

General karthief · Jan 17, 2025

Make sure that lower hose is tight.
I think you may have a better look at the side tank if the shroud is moved.
I would say don't go take'n the rad out before you pinpoint the leak.

Trogdor · Jan 18, 2025

I second the comment about using a pressure tester. If it is the radiator, I believe that Mishimoto has a lifetime warranty.

Mishimoto Radiator leak 1987 Foxbody 5.0

PHoffman

New Member

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Noobz347

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

Auto Pro Antifreeze and Coolant Leak Detector UV Dye 1oz | AutoZone

PHoffman

New Member

Auto Pro Antifreeze and Coolant Leak Detector UV Dye 1oz | AutoZone

gkomo

now i can hopefully expect to receive the shaft

PHoffman

New Member

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limp

wrap a little cheese around it and its a done

General karthief

wonder how much it would cost to ship you a pair

Trogdor

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Mishimoto Radiator leak 1987 Foxbody 5.0

New Member

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

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now i can hopefully expect to receive the shaft

New Member

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wrap a little cheese around it and its a done

wonder how much it would cost to ship you a pair

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