2.3-16 crack in plastic radiator tank

[Robby Ackerman]

The left side tank on my radiator has a crack in it right on the very top and just below the cracked area is where the upper hose attaches. I poured in a bottle of Gunk stop leak. What is the perferred method of repairing cracks in plastic radiator tanks? Do I replace the entire left side plastic tank or are there effective ways of repairing the plastic? Or once it starts cracking will it crack somewhere else?

[-fad]

repair vs. replace...?

I'd replace it with a whole new OEM radiator or a more high performance top quality radiator and enjoy piece of mind for the next XXX,XXX miles...

-fad

[pmizell]

Are you speaking of the plastic expansion tank right next to the strut mount?

If so, I wouldn't try to repair that, just order a new plastic expansion tank from FastLane. They're not that expensive -- like $26 I think.

G'luck

~Paul

___________________
'91 300E, 206k miles

[Robby Ackerman]

It isn't the plastic expansion tank next to the strut. It is the plastic tank that runs down the left (Driver) side of the aluminum raditor core. I didn't know if that plastic part is sold separately or if as FAD suggested, I should replace the entire radiator. It seems a shame to discard the whole rad because of an inch crack in a plastic componet. I'm still using the 42-year-old Behr radiator on my 190 SL. A new OEM radiator is around $300.

Fad ... you suggested an upgraded radiator. Do you have a particular brand in mind?

Robby

[MikeTangas]

Robbie,

A good radiator shop could replace the plastic tank (or both) on your radiator, but they are tricky. I have a friend who owns a radiator shop and he often breaks down the plastic radiators and repairs/replaces parts. If not done right, there will be leaks at the plastic/aluminum joints. This is the same guy I have do my brass radiators.

If it were my call, I'd opt for the OEM replacement rather attempt repair on the plastic.

[jeffsr]

GO with Mike's advice. You will quickly reach the point of diminishing returns trying to get the plastic replaced. And, remember, even if you get the tank replaced, the rest of that radiator is just as old as the part that failed.

[msyoder]

Hey Robby,

I'm sorry to hear about your radiator. I'm just now getting serious about what appears to be a leak in my heater core (see the thread on the Diesel list).

I was curious about your use of Gunk stop leak. Was this helpful in any way? Is it worth a try in my 300TD? I eyed the product at the parts store last week, but was nervous about adding something other than MB coolant and water to my system.

Thanks,

[Robby Ackerman]

Mike

Sorry to hear about your heater core. It is harder to remove than a radiator! I've used Gunk & Prestone radiator sealers and yes they work. I can't say at how many microns they are no longer effective, but for a heater core I'd sure pour in the sealer. The worst case is that the sealer could seal up the some of the cores in the heater if they were already marginal with mineral buildup. But hey, you need to replace it anyway.

I had to add a can of sealer to Pea Soup on the way to the races. It was 119 degrees on the track and the car's cooling was normal ... it wasn't adversly affected by having all that gunk floating around. I'm like you though in that I take pride in having clear looking coolant with just a touch of rose tint to it.

Thanks very much for the wool FDNY hat! I'll pass it along to one of the officers in our FD.

Robby

[ricali]

I would guess an after market replacement would be cheaper than an overheated block. The only time it will overheat of course will be a the worse time possible

[G-Benz]

Not sure if they use the same type of radiators, but I know classically on the W124s, the radiators crack at the joint where the inlet hose from the water pump is attached. This is where 99% of the radiators fail, and usually at over 100K miles.

The upgraded OEM radiators are reinforced with a steel shim inside the plastic intake junction.

New ones are around $300, and the install is pretty straightforward, even for a DIY'er with basic skills.

[Robby Ackerman]

Gentlemen:

Thanks for your advice. I'll order a new OEM radiator and new hoses while I'm at it, and I will plan on making it DIY job as soon as the parts arrive. It didn't split at at the neck where the top hose attaches. It has about a 3/4" crack in the flat top surface. I drove it 120 miles yesterday with no noticeable change in the water level ... this is after adding a can of Gunk stop leak.

One last question. The MB radiator on the car is a 140. I couldn't find a reference to the cap spec in my manual. All my other Benzes have 100 caps. Is the 140 cap correct for the 2.3-16?

Robby

[G-Benz]

I use a 140 cap on my W124, and I assume yours should be that as well.

MB OEM hoses are pricey, but on the flip side, they last nearly forever...so unless you have discovered any actual damage to the hoses, I would leave them alone.

I think someone posted a how-to on radiator replacement in the DIY section. It applies to the W124 series, but it should be similar to what you will encounter.

Note that the transmission cooler is also part of the radiator, so after you find the drain plug to purge the coolant, you will discover a metal line bolted near the area. When you disconnect that line, you will get a trickle of transmission fluid coming out, so don't let it drain into the same pan you are draining the coolant out...

[Robby Ackerman]

G-Benz

Thanks!

Robby

[-fad]

Hi Robby- just re-visited this tread and found your question...

I don't have a particular company in mind for the aftermarket- rad upgrade, however- - I believe that in the Hot Rods section, via search, folks make reference to upgrading the 500e radiator using an aftermarket company....

also, you may wish to do a flush engine cooling passages with the MB (powder'd/ acid?) when you do the rad replacement (for peace of mind and maintence)

good luck and hope this helps
-fad

[MikeTangas]

I believe that 1.4 bar is the current MB OEM cap rating, PartsShop/FastLane may still have some 1.2 bar in stock if you want a little lower pressure.