Coolant Leak and Type

[MrPulldown]

Our EVC recently developed a small coolant leak. This weekend I pulled off the engine cover and belly pan and started to inspect. It looks like the leak is coming from 2 places. One is the "T" coming off the upper radiator hose.

The other is connector I assume is from the Axillary Transmission cooler/stock cooler bypass.

The coolant lines going to the stock cooler are removed from and connected to each other when the Aux cooler is added. I tightened the hose clamps on the bypass and it seemed to stop the leak. I tried fussing with the hose spring clamps at the T but could not get them to release; bad working angle, I'll try again.


Question. Is this "T" or hose typically cracked and need replacing. Will I be successful if I pull the spring clamp back, rotate the hose on the T and reconnect the clamp. Sometimes this works to get a better seal. Any advice/recommendations is welcome.

Next it the question of coolant type. Read everything I could find but still never came up with a definitive answer. MY EVC calls for the discontinued G12 coolant. G12 is not G12++? Go-westy says that any phosphate free coolant should work.
https://www.gowesty.com/tech-article-details.php?id=12
A quick trip to the autoparts store yields 3 G-coolant options. All seem to have their own special blend. What do you all use?

I had removed some coolant from the tank and it appears to be in good condition. I suspect that the coolant was changed when the aux tranny cooler was installed a couple of years (<10K miles) ago. If I do need to change the "T" fitting I will need to drop a lot of the coolant.
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2002 EVC

[Joshwa]

It would say it’s common for the T to crack. I would plan on replacing T, since it’s an inexpensive part.
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93 Weekender TDI conversion (AHU)
93 MV TDI conversion (1Z)
Weekender rear cot
Late model cabin air filter on 93
Euro spec bumper install on 93

[ocelotpotpie]

I never mix coolants. G12 is discontinued but if you get G13 from the dealership it's entirely compatible. It's typically the same price as the parts store stuff, too. Local dealer price matched my online prices when they were a few bucks high.

That bypass looks like a plastic one. If I were you I'd hit a parts store and buy a brass fitting and maybe replace those clamps. See if you can get a better seal.

Like Josh said, the T connector does crack. I'd replace it with an OEM part or find a compatible brass option and use that.

Good luck!

[MrPulldown]

Anyone have a link to that "T"? Or a brass version. Some parts diagram show the lower rad hose with the "T", but non for the upper.
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2002 EVC

[MrPulldown]

So far I can not find the replacement part. Parts diagram show that it is PN
7D0121101N. However it is for the entire hose assembly (with the T) and cost about $100 if you can find a place that has it in stock.

https://www.ebay.com/itm/Radiator-Coolant-Hose-Genuine-For-VW-7D0121101N-/362529555251

Seems like someone should have made an aftermarket metal fitting kit by now.

Doorman makes a connector 627-006

https://www.amazon.com/Dorman-627-006-Radiator-Hos...mp;sr=8-14
However I think that it is for the lower rad hose T. Am going to dig in further this afternoon to measure some inlet piping sizes.

urrggg. I have never seen a factory coolant system with a maze of coolant lines like this before.
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2002 EVC

[ocelotpotpie]

There should be a generic brass part, you just have to find the right fitting. I'm not 100% sure which T fitting that is or which hoses sizes are there, but KBATTPO did a thread on the vortex about replacing his hoses. At one point he used a 1"x1"x1" T fitting, so it may be something like 1"x1"x1/2".

Here's that thread:

https://forums.vwvortex.com/showthread.php?8956625...ing-system

[MrPulldown]

[ocelotpotpie]

Happy to help! He has a bunch of "weak points" in the cooling system that he repaired in that thread, and he's a pretty thorough guy. We're lucky to have posts like that and members like him in our community.

[MrPulldown]

So I am wondering now if there is something that is causing these leaks to happen. Right now I count 2, but with the drips from the upper rad hose T, it looks like everything underneath is wet. Could my thermostat be going south and causing a pressure build up? Is there a check valve in the coolant lines that is stuck closed and building excessive pressure in the system. Seems like the van "gurggles" for a while after killing the engine. Do not recall this happening before.

I think I would like to R&R the entire cooling system. Aluminum crack pipe, t-stat housing, brass T fittings and possibly a new water pump. The van has 85K on the clock. I do have a week long trip coming up (~1K miles). Will it be safe to drive before getting this all fixed? It will take be a while to collect parts and prep for the work.

And what up with the electric water pump. I think I have located it and it is tiny. Is this used for circulating the coolant after the engine shuts down?
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2002 EVC

[ocelotpotpie]

If you aren't leaking enough to be triggering a low coolant situation and the van isn't overheating then I wouldn't stress about taking a trip with the drips/leaks.

A full R&R isn't a bad idea if you want to get in there and give it all a once over. The thermostats and plastic housings do get old.

The electric pump is just for circulating the coolant when the engine shuts down, as you said. It doesn't need to be that burly. You'd be surprised at how much those little motors can flow.

[VAEV1993]

[Zeitgeist 13]

Personally, I prefer convenience and accessibility vs OE provenance when it comes to consumable fluids. Since all my vehicles are either VWs or MBs, I run the same fluids in each. Valvoline is the OE coolant manufacturer for MB, and Zerex G05 used to be their formula, while G48 is their updated but compatible version. VW and MB use the same suppliers for metals, rubbers and plastics, so if Zerex is good enough for MB it's good enough for VW. I'm presently running G05* is all my rigs, but my switch to G48 if that phase out the former. Zerex is available nationwide at nearly all the chain stores.

*I like the concentrated bottles vs the 50/50, since I don't feel like paying for half a container of water.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[MrPulldown]

[MrPulldown]

I threw on 2 worm gear hose clamps on the leaking T fitting. Was afraid that if the fitting was cracked the pressure from the clamps would further crack the fitting. Possibly completely crush it. I purchased the Doorman unit, and it looks like the right size. Did no install, just had on hand in case. Both upper and lower radiator pipe Ts are the same size as far as I can tell. I did not drain the system, simply slid the spring clamps down. SO there is kind of 2 clamps at each joint.

Made the 300 mile trip. Did not notice drips along the way. Defiantly slowed down the leak, but at our finale destination a few drops did accumulate on the driveway after an hour parked in the same spot. No real noticeable drop in reservoir levels; maybe a 1/4 the distance from max to min.
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2002 EVC

[MrPulldown]

I thought that I would follow up on my leaking coolant lines. This weekend I finished replacing the plastic coolant line fitting and the OE spring clamps with a selection of brass, stainless steel and worm gear type hose clamps. I based it off the the thread linked earlier and this PDF. I circled the 3 items that I replaced. It also turns out that the "T" fitting off the upper radiator hose was not cracked. Just that the clamps were no longer able to keep the fluid back. With the plastic fitting I was afraid to crank down on the hose clamps tight enough to stop the drips.

The Doorman part I had purchased to have on hand in case the fitting blew out on me is an exact replacement for the OE unit. The sharkbite brass fittings were easily sourced from the hardware store. The 1.25" stainless barbed connector I found on Amazon. This would have been much trickier if I did not deleted the coolant lines going to the OE transmission cooler. I had installed an external transmission cooler and the OE coolant to ATF cooler was removed. The left over cross over was no longer needed and the connector was also one of the joints that was failing and leaking.

Here is the amazon part:
https://www.amazon.com/gp/product/B08DTT4331/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

If I did need to keep the "T" and the trans of trying to replace the lower radiator pipes "T" you could use a 1.25" "T" and reduce the side line to 1".
https://www.amazon.com/Beduan-Stainless-Barbed-Spl...amp;sr=1-5

With the "death star" coolant reservoir removed the job was pretty easy. Draining was easily done via the crack pipes drain screw. I also removed the
upper grill and the radiator support. This gave me more room to work. I mixed in a gallon of 50/50 G40 and reused the old coolant as it was recently replaced and still very fresh. It mixed fine suggesting that the drained coolant was not G12.

Test drive showed no signs of leakage. IT does seem like there is a slight hiss or fluid noise. Might be a result of the deleted line and the new fluid dynamic presented by the 90 degree elbow instead of the "T" (on the back side of the deleted ATF coolant line). THe last post of KBATTPO's thread suggest that there is a performance increase as a result of this delete. He also mentions "straight" fitting not a elbow. Wonder if this was a generic statement or if he really went with a straight union.
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2002 EVC

[bigfoot_ev]

While I was chasing down a minor coolant leak it looked like there were just too many hoses and connectors under the hood. So, I removed a bunch.

It's amazing how much simpler the cooling system can be when you remove the transmission cooler and the rear heater box! I can actually see the top of my transmission now just looking under the hood. Once I understood which hose went where, I ordered the pex sharkbite fittings I needed as outlined in the diagram above. I kept one of the large plastic tees, but since I eliminated one of them with the 1-1/4 straight coupler I now have a spare.

I ended up getting:
1" elbow
1"x1"x1" tee
1"x1"x1/2" tee
1"x1"x3/4"
1" coupler

And replaced the spring clamps with worm-drive smooth band stainless clamps. I filled the system with Febi G13 coolant from FCP Euro. No more leaks.

I know removing the rear heat is not for everyone, but you could always add a diesel heater. If anybody needs a rear heater I have one...free.
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2003 Westfalia Weekender, AXK, 01P

[dsh1705]