Patch leak in radiator expansion tank? Universal tank options/DIY?

[ttgg89]

Hello, I have an '89 dodge Grand Caravan, found a leak in the non-pressurized radiator overflow tank. I have a place where I can work on the vehicle but I have to drive there then button up and drive away the same day. Hence I found a used tank on Ebay to have ready to install.

Not surprisingly the 30 year old used tank had a leak as well, one lower corner rests on the frame and over time the seam in that area lets go. Cleaned it up real good inside and out then after a bunch of research chose JB Water Weld epoxy for the patch. Supposed to be good to 300 degrees and read some related patch reviews on amazon that sounded good to go.

Held for a few days now starting to seep. I had roughed the area beyond the patch, filed a slight groove down the leak area in the seam, and cleaned with Acetone. After what I read kind of surprised it didn't work. So, now I need to clean up and patch the original tank and try again.

Any ideas on glues? I thought of plastic welding as well but I gather that's a bit tricky. Also any ideas on the patched tank, dremel off the old adhesive and try again?

I have on hand: JB ClearWeld, JB Weld, JB Water Weld, Shoe Goo, E6000, Marine Goop.

I found a couple of threads here, one spoke highly of Glue-All for plastic fuel tanks but I think it's only good up to 150 degrees.
https://www.garagejournal.com/forum/showthread.php?t=446227

Initially I had done a search on some kind of new universal tank replacement, most seemed geared towards the pressurized type of tank. Found a few rather primitive looking diy options, any ideas there? Plenty of room in the engine compartment [4 cylinder with AC removed], doesn't have to be pretty.
thanks
First pic shows the seeping patch after removal:

 

[The Cobbler]

my buddy used to fix plastic gas tanks with a soldering iron with good results , heat up the plastic & smear it around. since you have a spare tank, cut a pc of the plastic off & use it as filler rod.

 

[ttgg89]

thanks for the encouragement, yeah there's a whole bunch of plastic weld stuff on youtube to look at, I have some heavy large zip ties that looked possible as filler and a heavy old 5 gallon water jug as well. I have messed with a copper wire in a soldering gun to cut styrofoam to size... I don't think I want to cut up any of my original reservoirs, I was amazed to find one on Ebay, no others in sight. They are long out of production and most of these old caravans got crushed a long time ago.

 

[ttgg89]

OK well I found the mother-lode of DIY stuff over at Jalopy Journal, looks fun! I gather my type system just needs a tube cut at an angle going almost to the bottom of the container and some kind of vent in the top. I also located the mopar part number [4401305] and interestingly found several NOS examples in... Germany! Found out as well that that tank was used in a number of Mopar vehicles.
https://www.jalopyjournal.com/forum/threads/overflow-bottle-ideas.512324/
https://duckduckgo.com/?t=ffab&q=puke+tank+site:https://www.jalopyjournal.com/forum/&ia=web
https://duckduckgo.com/?q=expansion...://www.jalopyjournal.com/forum/&t=ffab&ia=web

 

[bcschief]

False economy Autozone lists a Dorman P/N 603-001 For $9.99 and it looks like a square box

 

[kald]

If it is Nylon 66 then it can't be fixed by welding or gluing.

 

[seber]

It is probably polypropylene. There is no adhesive that will stick to that. It is also resistant to solvents. Welding is your only hope. There are plastic welding guns that work like a hot melt glue gun but with higher temp. If you are good enough, you can try heating with whatever and weld a piece of one of the tanks to the other.

 

[sberry]

False economy Autozone lists a Dorman P/N 603-001 For $9.99 and it looks like a square box

I price new first if I can on something like that. Sometimes surprised.

 

[ttgg89]

Well I contacted the Ebay seller in Germany, about $85 shipped to USA. Not too bad I guess, it's brand new, NOS, even has the Mopar box! Mulling it over, may try the plastic welding, see below. thanks

False economy Autozone lists a Dorman P/N 603-001 For $9.99 and it looks like a square box

Thanks, I had seen that... cheaper at Amazon with a $25 order minimum. It won't fit the space.

I price new first if I can on something like that. Sometimes surprised.

Thanks, went to the dealership, none available, out of production

my buddy used to fix plastic gas tanks with a soldering iron with good results , heat up the plastic & smear it around. since you have a spare tank, cut a pc of the plastic off & use it as filler rod.

Dare I try plastic from something else? squeamish about cutting up a hard to find tank.

It is probably polypropylene. There is no adhesive that will stick to that. It is also resistant to solvents. Welding is your only hope. There are plastic welding guns that work like a hot melt glue gun but with higher temp. If you are good enough, you can try heating with whatever and weld a piece of one of the tanks to the other.

Thanks, very helpful on the adhesive, that explains it then. Dare I try plastic from another source? Squeamish about cutting up hard to find part. I have some thick foot long zip ties, also a 5 gallon heavy water jug I don't mind cutting up, material looks similar.

 

[SeisMec]

Regarding NOS plastic anything - it's been off gassing since the day it was manufactured and so becoming more brittle.

If the zip ties are HF, they are not HDPE (or maybe it's been recycled about a bajillion times)- use quality zip ties, buy rod or look for the appropriate resin symbol/number on what ever you're scavenging your plastic from.

Most 5 gallon buckets are HDPE. You might want to practice on one of those before you try fixing the tank.

FWIW I had good luck fixing a gasoline tank using a heat gun and HDPE rod.

 

[ttgg89]

Regarding NOS plastic anything - it's been off gassing since the day it was manufactured and so becoming more brittle.

If the zip ties are HF, they are not HDPE (or maybe it's been recycled about a bajillion times)- use quality zip ties, buy rod or look for the appropriate resin symbol/number on what ever you're scavenging your plastic from.

Most 5 gallon buckets are HDPE. You might want to practice on one of those before you try fixing the tank.

FWIW I had good luck fixing a gasoline tank using a heat gun and HDPE rod.

Thanks, good point on the off gassing. At this point I am strongly leaning towards just temporarily sticking some kind of bottle in there, if only to see the concept work: recovery tube going to near bottom of container, breathing hole in top. Fortunately it's not an emergency, my patch is just barely seeping after it's been run a bit.

By "HF", do you mean Harbor Freight? These are some monstrous zip ties I found at a yard sale, I believe they may be industrial high quality. Thanks for the plastics link and encouragement on the gas tank repair success. I am going to proceed collecting info from youtube vids.

 

[Coach James]

I put a universal tank from Advance on my 90 Dakota a few years ago. It still works fine.

Last month, I put a new tank on my 2000 Frontier. It was an exact copy of the OEM tank. I got it from Rock Auto for ~$10 bucks. Took maybe 5 minutes to change. When I can get a exact copy of the original tank for that price, no way I would try to fix an old tank unless I just did it for fun.

Coach

 

[bargainhuntingking]

I’ve used POR-15 with success on the inside of two metal containers that had rust holes, after derusting with Evaporust. I also used JB Weld on the outside and then painted them. No leaks. One is a 5 gallon Jerry can and the other is the (pressurized!) gas tank of a Coleman 425 stove. I’m gonna die, I know.

POR-15 is a great product, but even 8oz is ~$15

 

[seber]

Zip ties are nylon. That's a no go. Plastic bucket should work.

 

[matt_i]

I would use RockAuto as suggested.

But if you want a lights-out permanent solution then design some parts and send to your online laser cutter in stainless and then tig weld the thing to pressure-tight. Its a bit of overkill but it won't leak any more.

 

[2oolhound]

I wouldn't plastic weld with old plastic from something else just because it "looks like the same". I did that with my lawn mower and it didn't work, leaked after a day. Now I've melded a bigger area of the original tank with the wrong type plastic so it needs a much bigger repair.

I fixed my rad on a 2000 cherokee welding with a solder gun. It worked so good when I laid a hot welding rod against my coil type airline and burnt a hole in it I welded it too. It's been holding air for a couple months now. A solder gun and the right filler rod is key.

 

[JKU]

Flex Seal? That would make it 1,002 uses..... they say it's good -80 to 350F