Offering possible solution for cracked coolant tanks

[fasterjames]

After searching through this awesome forum, it seems that Coolant Tank fractures are common in the Boxster. Fortunately mine has not broken yet but it seems inevitable.

Thinking about this, I have a possible solution I'll throw out.

1. Has anyone ever tried repairing these with either a hardened epoxy or a semi-flexible epoxy?

2. Or has anyone ever covered the coolant tank with an epoxy to help provide longevity to it?

As a hobby I am restoring an old mahogany runabout and have been using various types of epoxies. These are not your Home Depot/Lowes everyday super stong epoxies. These are actually made to be able to hold a sea-worthy boat together of up to 40 feet in length without screws. ( a smart builder however would still use screws.) Fiberglass is a sponge compared to this stuff. Needless to say it's nasty stuff to work with but some of them have a similar consistency to the ABS plastic used in automobiles and in particular the coolant tank.

I was thinking that if the tank was already cracked, this could be applied and would most definately seal the crack forever. If not cracked it may be a good deterent to breakage. They can handle stress like you can't believe and are very heat resistant too.

There are some that have zero flexibility (West Marine for example) and some that allow just a small amount of flex. Im not sure how much heat they can take but do know that before mixed and cured, the boiling points of these products are typically around 200 degrees which would make me think that cured they could withstand temperatures much much higher.

I am not a chemist but have learned a lot about using this stuff and am very impressed. Anybody have any thoughts on this?

[JFP in PA]

After searching through this awesome forum, it seems that Coolant Tank fractures are common in the Boxster. Fortunately mine has not broken yet but it seems inevitable.

Thinking about this, I have a possible solution I'll throw out.

1. Has anyone ever tried repairing these with either a hardened epoxy or a semi-flexible epoxy?

2. Or has anyone ever covered the coolant tank with an epoxy to help provide longevity to it?

As a hobby I am restoring an old mahogany runabout and have been using various types of epoxies. These are not your Home Depot/Lowes everyday super stong epoxies. These are actually made to be able to hold a sea-worthy boat together of up to 40 feet in length without screws. ( a smart builder however would still use screws.) Fiberglass is a sponge compared to this stuff. Needless to say it's nasty stuff to work with but some of them have a similar consistency to the ABS plastic used in automobiles and in particular the coolant tank.

I was thinking that if the tank was already cracked, this could be applied and would most definately seal the crack forever. If not cracked it may be a good deterent to breakage. They can handle stress like you can't believe and are very heat resistant too.

There are some that have zero flexibility (West Marine for example) and some that allow just a small amount of flex. Im not sure how much heat they can take but do know that before mixed and cured, the boiling points of these products are typically around 200 degrees which would make me think that cured they could withstand temperatures much much higher.

I am not a chemist but have learned a lot about using this stuff and am very impressed. Anybody have any thoughts on this?

After going thru the greif to get the unit out, I'd rather put in a new one..........................

[986Jim]

I think he is saying you could seal it without pulling it out. Problem is if this stuff is applied with wet coolant on the tank would it cure? If you had to pull it out to cover it as already stated, thats most of the work there, might as well put a new oem part in and be good for 6 years to come again...

[Tool Pants]

I would like to see one made of metal. As far as I'm concerned the plastic versions are all going to fail sooner or later.

In my younger days I had a 1975 and 1981 Fiat X1/9. Mid-engine with the tank in the engine compartment. The 1975 had a metal tank, stainless steel, and I had that car for years with no tank problems. Lots of other problems, but not with the tank.

The 1981 was fuel injection and had a plastic tank. I went through a few plastic tanks. Then I went to a wrecking yard and got the metal tank like my 1975 had and put it in the 1981. Back dating to the metal tank solved the issue.

[986Jim]

One other solution we run in our race cars is Waterless Coolant. It's coolant with no water in it, it's glycol or some type of alcohol. It has zero expansion when heated super hot so your coolant system is never under pressure anymore, it also will not boil in the engine with a boiling temp of over 400* C. We don't even run an expansion tank in our race cars because this stuff doesn't expand so you just pour it in and seal it up. We can run the car all day then pull the rad cap off and the water is just sitting there. It's hot, but not under pressure.

This is perfectly safe for a street car and would allow us to totally eliminate our expansion take entirelly. How about that?

http://www.evanscooling.com/catalog/C_npg1.htm

[Topless]

Yes exactly!

Porsche does a lot of things very well but this pressurized poly coolant tank is a joke. Anytime you subject molded plastic to daily cycles of heat and expansion it will surely crease and crack over time. It is not a case of "if" but "when". I guess all those years with air cooled engines they got behind the curve on this.

If it were up to me I'd want a cast aluminum tank with minimal fittings, no vis window and all the tubing routed through the firewall so any needed maintenance could be done from the trunk. I'd still use 50% water solution because I drive all over not just on a track. If I developed a coolant leak somewhere out in BFE I could repair it, top it off with plain water and drive it home. Then I could just flush it and add proper coolant.

In large quantities an aluminum tank could probably be produced for about $20 ea. I would guess. It seems like a retrofit kit could be very profitable considering what Porsche is getting for the cheesy plastic ones. Maybe a nice little side business for someone with the time and talent.

[Tool Pants]

I have not seen a 2007 3.4 Boxster yet, but for some reason I think the tank is no longer in the rear trunk. If this is true I hope Porsche came up with a better design because the past history and all the generations of Boxster plastic tanks that have failed is not good.

[Topless]

Maybe they finally got religion.

[PTEC]

Yeah the expansion tank on the 07s is no longer in the rear trunk. It uses the same type of system as the Cayman. Still plastic though.

Edited October 4, 2006 by PTEC

[Tool Pants]

This is the Cayman plastic tank in the engine compartment for those who have not seen it.

[Topless]

Certainly looks like a design change...fittings on the top and easier to get to :D . It is still molded plastic so it's gonna crack someday :( .

[Tool Pants]

Saw my first 2007 Boxster today. Tank in the trunk is gone. I assume it is now like a Cayman.

http://www.renntech.org/forums/index.php?showtopic=10979

[Loren]

At least when it leaks now... it won't get the contents of the trunk wet :lol: :lol: :lol: :lol:

[PiG]

After searching through this awesome forum, it seems that Coolant Tank fractures are common in the Boxster. Fortunately mine has not broken yet but it seems inevitable.

Thinking about this, I have a possible solution I'll throw out.

1. Has anyone ever tried repairing these with either a hardened epoxy or a semi-flexible epoxy?

2. Or has anyone ever covered the coolant tank with an epoxy to help provide longevity to it?

I did an emergency repair on my 996 coolant tank whils in the pyrenees in Spain this summer. I used epoxy with stainless steel fine mesh sandwiched in-between.

It worked fine for 1000miles, but failed on the nurburgring. Basically, the engine bay temperature ended up higher than the melting point of epoxy (only about 70C) and the epoxy broke down and melted.

As a temporary fix to get me home it worked, but it isnt a long term solution.

I paid £56 UK for a new tank from the OPC so given the hassle getting the thing in and out of the engine bay, just getting a new tank is a no brainer really.

Cheers

Paul

[Charlestonboxster]

This is perfectly safe for a street car and would allow us to totally eliminate our expansion take entirelly. How about that?

http://www.evanscooling.com/catalog/C_npg1.htm

Well, it's my turn.

Coolant tank been leaking slightly, about a quart every week, for about 6 weeks now. Warning light worked perfectly, I now check every few days, and keep topped off every few days.

Typical coolant traces in trunk area discernible once I removed wood liner, of which a part is now mostly mushy/soaked and in the process of drying... :angry:

Does anyone believe the above coolant is compatible with our engine, and could be a safe temporary solution to my slow leak problem until I replace the tank? :lightbulb:

That's assuming that this coolant does not expand as much as standard coolant, if at all, therefore present leak will be minimized.

If so, is it possible to replace most of the coolant without a complete flushing of the system?

I'm wondering is a complete coolant flush is almost as much work/trouble as simply replacing defective tank.

Thanks for any input.

Tony

[Tool Pants]

Towards the end I was adding almost a pint a day. I used just tap water.

When I replaced my tank I removed the hose from the back of the tank, so I lost only about a cup from the tank. I reused the coolant when I put in the new tank.

You do not need to flush or bleed for a tank replacement. The tank is the highest point so the most coolant you will lose is what is in the tank.

[Charlestonboxster]

Towards the end I was adding almost a pint a day. I used just tap water.

When I replaced my tank I removed the hose from the back of the tank, so I lost only about a cup from the tank. I reused the coolant when I put in the new tank.

You do not need to flush or bleed for a tank replacement. The tank is the highest point so the most coolant you will lose is what is in the tank.

This makes the task less daunting. TP, thank you for the clarification, it looks like tank replacement is my best bet, done as per your thread/photos.

I was a bit confused at the choices, between 986 and 987 tank, would it be correct that your eBay tank ordered a while ago was a most recent 986 model replacement, and if I order from Sunset now, the 987 wouldbe the best choice and/or most recent update?

This is the one with the whole you pop out?

Thanks!

Tony

[Tool Pants]

The 987 part is the current part, and that is what you will get unless they have old stock lying around. I bought the ebay 986 tank a long time ago.

Simply remove the plastic plug on the 987 tank for the dip stick tube.

[nick49]

I have a plastic welder and have have repaired both ABS and PVC motorcycle fairings, ATV fenders and bodies as well as gas tanks successfully since the late '80s. I also attempted to repair my 996 coolant tank which is polypropylene, but for some reason it would not weld as other plastics. It seemed that as soon as the poly rod was hot enough to melt it would form an oxide skin as would the tank plastic and the two would almost repel each other. They would not attempt to flow or bond. I cleaned this up and used a high heat industrial epoxy and filled the crack that I had previously cleaned and veed out. It looked like a great repair. It lasted about 2 weeks and started to seep again. I ended up buying the latest part and it's been OK so far.

[Charlestonboxster]

Thanks Tool Pants,

I will order 987 Tank, Install, and share the time it took me as an amateur, for others to know.

T

[Peer]

PiG wrote:

> I paid £56 UK for a new tank from the OPC

I wonder if someone in the US sells the coolant tanks for such a human price?

Any pointer appreciated.

-- peer

[Tool Pants]

I was very lucky and got mine from ebay for $90 2 years ago. http://www.renntech.org/forums/index.php?s...5&hl=Geiger