95 Mustang GT - constant radiator issues

da8banger

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Hey everybody,
I'm new to the forum. I've been having issues with my new-to-me 95 Mustang GT (5 speed, in Black). I am the 2nd owner, and so far its at 125k miles. Since getting the car last December, it's been running rock solid. Everything is stock in this car except for some common repairs (idle air control and clutch were replaced by the owner). I have been putting as much TLC into the car as much as I can (etc tune ups, new suspension, new short throw shifter, detailing, etc). The car has been running amazing for the most part.:)

However... I have been pretty much battling my radiator since I got this car. Does anyone have any advice?

starting in January I have noticed the OEM radiator dripping small amounts of coolant in the morning. I found that it was leaking coolant when the engine is under load at the plastic end tank seams. I swapped it out for a SVE 3 row aluminum radiator from LMR in February. I only swapped the rad. Did not swap the hoses, nor the reservoir tank. After 1 month, the radiator popped while I was driving home from work near the upper rad hose. I thought it was the hoses, so I replaced both the upper and lower. I tried pressure testing it after and found that the leak was actually coming from right next to the upper rad hose, on the end tank seams!! I was still under warranty I got a replacement SVE rad from LMR, and swapped that one in. It's been about a month now, and seemed to be working fine but now on this 2nd SVE radiator the rubber drain plug somehow got loose while I was driving and coolant started leaking over the freeway like water!

I plan to make some kind of metal stopper to replace this cheap rubber drain plug, but I can't believe it would just come out while driving. The roads here can get a little bit bumpy, but that shouldn't be enough to pop the plug out right? I am thinking there might be some bigger issue with the pressure somehow... maybe the pressure gets too high, and it tries to find the weakest link (in this case it was the drain plug, and not the end tank seams, so the pressure pushes the rubber stopper outwards). I'm not a mechanic, but this is the third radiator in this car which seems highly unusual. Maybe the SVE quality is just really bad? I can't believe the OEM Ford one has pretty much lasted for ~30 years but these new radiators can't even last 1 month. This is the radiator I had bought. https://lmr.com/item/SVE-8005B/1994-95-Mustang-Aluminum-Radiator-for-Manual-Transmission

FYI, I am not having any other leaks or issues. Head gasket is fine, and my coolant temp sensor is working properly. The OEM coolant reservoir tank is not leaking either.

Other questions:
1. Is there any thing I need to replace besides the radiator and upper/lower rad hoses to future-proof my car from future leaking radiators?
2. Would a lower PSI cap help? I believe the SVE cap is 16 PSI or whatever is the same as the stock rad cap PSI.
3. Can high pressure due to too much coolant cause radiators to pop? I am thinking its better to run a little bit less coolant than usual as long as the engine is not overheating to avoid pressure issues.
4. Any radiator suggestions for reliability in case I have to replace this SVE one?
 

shovel

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I believe autozone still rents radiator and cap pressure test kits, you can pressure test your cap to make sure it's not accidentally a 10bar unit. And make sure the hose between your cap and overflow tank (and the tank itself) aren't plugged with guacamole or wasp nests or whatever because the pressure rating on the cap is before the overflow opens, not the top seal.
 

cobrajeff96

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It's good you have the Mishi floating brackets, but yea the pinhole leak at the end tank of the new welded radiator just means QC issues at the assembly place (probably somewhere in mainland China if I were to guess).

Most cars are supposed to be at 16psi and don't try to reduce it because if you do the boiling point of the coolant system will also reduce. In a perfect storm situation (very hot day and spirited driving) you might actually damage the block. Racing cars go higher like 22 as the engine can run hotter safely because a hotter motor makes more power.

I don't trust radiators with those petcock drains anymore, ever since I put in a Mishimoto rad about 8 years ago. It's a thread in drain with a copper crush washer so there's no way it can come loose or leak.

I think you just got unlucky with bad quality hardware.
 

tvsn95

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I went through 3 3 row Alum rads in 2 months...they were ebay crap,, got 2 weeks out of the last one. they replaced them all and finally sent me a refund. I don't know why I thought I needed a hot rod Rad.
Back to stock and running for Years with AC and Turbocharger. I ONLY run 18lb caps, just my preference, no need to argue with me.
One thing that is not obvious is the old fan motor will slow down and cause overheating (Bushing in the motor ) at low speed. also draws too muck current and burns the plug connector at the fan. Common problem . just replace the motor.
All of the turbo/supercharged cars I built for other ALL use stock rad's. only had one fail and we still don't know why, I suspect owner crazy shit. but ??
 
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da8banger

da8banger

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I believe autozone still rents radiator and cap pressure test kits, you can pressure test your cap to make sure it's not accidentally a 10bar unit. And make sure the hose between your cap and overflow tank (and the tank itself) aren't plugged with guacamole or wasp nests or whatever because the pressure rating on the cap is before the overflow opens, not the top seal.
Thanks for the tips. I ended up flushing my coolant system out based on this advice. The coolant was coming out clean anyway, so I guess this was not the problem.

I will need to pressure test sometime when I get the chance
 
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da8banger

da8banger

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It's good you have the Mishi floating brackets, but yea the pinhole leak at the end tank of the new welded radiator just means QC issues at the assembly place (probably somewhere in mainland China if I were to guess).

Most cars are supposed to be at 16psi and don't try to reduce it because if you do the boiling point of the coolant system will also reduce. In a perfect storm situation (very hot day and spirited driving) you might actually damage the block. Racing cars go higher like 22 as the engine can run hotter safely because a hotter motor makes more power.

I don't trust radiators with those petcock drains anymore, ever since I put in a Mishimoto rad about 8 years ago. It's a thread in drain with a copper crush washer so there's no way it can come loose or leak.

I think you just got unlucky with bad quality hardware.
Great advice thank you. After I posted this thread, I had ended up replacing that rubber drain plug with a copper one. Holds much more securely, don't think it will leak from there again.

I still had the rubber drain plug from my previous radiator, and compared. It looked like the rubber plug's teeth warped (I guess under heat + pressure does that?? :rolleyes:) and it compromised the seal
 
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da8banger

da8banger

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I went through 3 3 row Alum rads in 2 months...they were ebay crap,, got 2 weeks out of the last one. they replaced them all and finally sent me a refund. I don't know why I thought I needed a hot rod Rad.
Back to stock and running for Years with AC and Turbocharger. I ONLY run 18lb caps, just my preference, no need to argue with me.
One thing that is not obvious is the old fan motor will slow down and cause overheating (Bushing in the motor ) at low speed. also draws too muck current and burns the plug connector at the fan. Common problem . just replace the motor.
All of the turbo/supercharged cars I built for other ALL use stock rad's. only had one fail and we still don't know why, I suspect owner crazy shit. but ??
Wow that's crazy man. Looks like stock rads are the way to go, besides the more expensive mishimoto rads. If this rad craps out on me again, i'm gonna try to salvage it like Musturd mentioned. otherwise will just order a stock rad.

thanks for the advice on the motor. I will look out for that. :)

I was also doing some more research and just realized I am missing the rad air deflector trim piece on the bottom of the car. It looks like it got ripped off by the prev owner maybe over a curb or something. I ordered one of those and will install it, and hope that it can also help with the cooling.
 

tvsn95

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for what its worth
If you have a regulated air source, you can apply 15 lbs of air backward into the over flow TUBEING. this will cause all your leaks to show.
 
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da8banger

da8banger

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for what its worth
If you have a regulated air source, you can apply 15 lbs of air backward into the over flow TUBEING. this will cause all your leaks to show.
good advice thanks.

Unfortunately this SVE radiator is now leaking. Again after 1 month... Going back to stock and hoping for the best.

Thank you for the help!
 
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da8banger

da8banger

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Hey fellas just to update been running a stock style Duralast rad from autozone since the incident. Running strong so far, no leaks. been a month now! cheers thx for the advice!
 

Daryl

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Glad I retained my stock rad, but very happy and no issues whatsoever with the Mishimoto rad, brackets, upper and lower hoses. About a year-ish now +/-
 

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