Another Mishimoto coolant tank leaking - new suggestions?

[NvrFinished]

Long story short, my Mishimoto coolant tank is leaking. Unlike this thread where the OP had a problem with the site tube, mine appears to be leaking from both the upper and lower fittings for the site tube where they screw into the bung hole. There is residue that runs from both fittings to the bottom edge of the tank. I only have 10,000 miles on the car with about 8,000 on the Mishimoto tank.

I just recently started loosing coolant and put this on my list of things to check when I had my front bumper off for grille mods, APR front splitter, brake cooling and etc. After pulling the bumper I can see where coolant got everywhere and I now have a big mess to clean. I'm frustrated as I keep my car clean and the last thing I wanted was a sticky mess everywhere below and in front of the engine that collects dust and dirt and turns into black looking crud. :frusty:

I went with the Mishimoto tank because I liked the usefulness of the site tube, but now I don't trust it, even if I clean and re-tape the fittings. I track my car on road courses and don't want this issue again.

Any suggestions on a good looking replacement? The Moroso coolant tank looks similar, just no site tube to worry about.

[MENTION=9961]Mishimoto[/MENTION]

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[tom_sprecher]

I went with the Moroso because I was worried about the site tube leaking and the welds look much better. While I would prefer being able to easily check the coolant level, I did not care for the execution on the Mishimoto unit. They make brass push on pneumatic connectors, so do a search and maybe replace the plastic ones.

Here's what I'm talking about.

https://www.fastenal.com/products/details/441046-131280?r=~%7Ccategoryl1:%22603388%20Hydraulics%209and%20Pneumatics%22%7C~%20~%7Ccategoryl2:%22611532%20Fittings%22%7C~%20~%7Ccategoryl3:%22603422%20Push-to-Connect%20Fittings%22%7C~%20~%7Ccategoryl4:%22603429%20Elbows%22%7C~%20~%7Csattr03:%5E%22Tube%20x%20Male%20NPTF%22$%7C~

 

[NvrFinished]

Thanks for your input on the Moroso tank, Tom. The site tube is not leaking at the connection points, it's leaking where the connectors are threaded into the bung hole.

 

[tom_sprecher]

Are the existing connectors plastic? Are they NPT? If yes to both use nickel plated brass connectors and some Teflon pipe sealant.

 

[NvrFinished]

Are the existing connectors plastic? Are they NPT? If yes to both use nickel plated brass connectors and some Teflon pipe sealant.

No and yes. The connectors are plastic while the threads are brass NPT. Here is a pic.

 

[tom_sprecher]

Bad threads in the bungs? Leaking between the plastic part and brass, or plastic part and tube? The ones I linked have no plastic parts and should have the same expansion/contraction rate helping to prevent leaks.

 

[NvrFinished]

I appreciate the help, Tom. The coolant is leaking where the connectors are threaded into the bung. Mishimoto used what looks like Teflon tape, but they ended up leaking nonetheless. I could clean the threads and re-tape or purchase the connectors you linked to, but I'm worried about it happening again. Since you have to stop threading the connectors in at an exact point to line them up, I'm wondering if they didn't get tight enough and that is the issue.

 

[Dr. Norts]

Looks like they used white Teflon which isn't the greatest. Take those fittings out and clean the old Teflon off of them.

Then get some pink Teflon tape or use some pipe dope and it'll never leak again.

 

[Shocker]

Get some Blue Monster Teflon tape. I use it at work and it holds up to raw bleach, nitric and caustic acid without leaks.

 

[Dr. Norts]

Get some Blue Monster Teflon tape. I use it at work and it holds up to raw bleach, nitric and caustic acid without leaks.

Blue monster is awesome. It's my favorite Teflon tape. I just suggested pink because it's easy to find and works just as well. It's just not quite as easy to start on the threads like the blue monster brand.

 

[NvrFinished]

Yeah, I'm debating whether I want to do that or not. I just don't want any more coolant issues. I'm going to contact Mishimoto as well and see about getting their updated site tubing as well.

 

[robwlf]

dont use teflon tape at all .. go get some pipe dope at lowes or a hardware store..or plumbing supply place ... if it leaks after that.. id just get a diff one .. pipe dope will work the best imo

 

[Mishimoto]

Hello Everyone

Sorry to hear about your sight tube issue NvrFinished. We have since revised the material used for these tubes and have them available for anyone with problems. In your particular situation, if you contact us directly and we are able to determine that there is an issue with the threads on your tank, we could very likely get the entire unit replaced under warranty. Send a quick email to [email protected] and the team would be happy to help out.

Thanks
-Jake

 

[Genxer]

See if the leak is around the threads itself or the joint of the fitting. If it’s the threads you should be able to get it sealing. The thread tape and also making sure it’s tight. NPT fittings are tapered and may need to be snugged. My replacement tubing from Mishimoto came with new fittings that look the same as original to me. Haven’t installed it yet to see results. If I do everything will be getting checked quite often for signs of degradation.

 

[Brent Dalton]

I'd put the stock one back in.

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