Coolant Leak Sealer

[Dave 53]

(Last post tonight, I promise)

On top of my car running rich... I've got a slight intermittent coolant leak.

It's only happened twice and self-repairs after a few miles. A small amount of coolant seeps onto the floor below my peddles. Not enough to even really notice any missing from the expansion tank, but enough to make the floor slippery. I clean it up a couple of times and it stops doing it. The commonality is it's after driving for a while, then stopping for about an hour. Restart - leak.

I suspect it's the hose clamp for the hose connecting the pipe that runs under the door that goes past the tire to under the hood. The coolant seems to be seeping from under the sheet metal piece covering the hose by the dead peddle.

I proper mechanical tightening of the hose clamp will require taking the door and all left side body panels off!

Coolant leak sealer products.... 6 or 7 different products at my local auto parts store. Seeing as how this is a small intermittent leak and getting to the hose clamp is a huge project, a coolant leak sealer product is sounding pretty appealing.

Good idea? __________ is the best product.

Or bad idea - tear the side of the car apart and tighten the hose clamp.

[egchewy79]

rent a pressure tester from your local napa or other auto store. they will typically loan the tool for free, but keep your CC# on file in case you don't return it. attach it to your filler neck and pump up to 16psi. wait and listen/look for the leak. this will at least give you an idea of what/where you're having the problem.

[mikeinatlanta]

Sealers don't do well with a leak from a hose connection. While a pain to get to, I suggest replacing the clamp with a Gates Powergrip. If that joint can be made to not leak, the Powergrip clamp will do it. If it leaks with Powergrip then something is wrong.

[cgundermann]

Concur w/Mike, never have I had a Gates leak!

Chris

[Dave 53]

Sealers don't do well with a leak from a hose connection. While a pain to get to, I suggest replacing the clamp with a Gates Powergrip. If that joint can be made to not leak, the Powergrip clamp will do it. If it leaks with Powergrip then something is wrong.

Gates Powergrip... never seen that before. Sealers don't work well on hose connections. Love the wisdom of this forum! Thanks!

[niceguy]

I love the look of Gates Power Grip clamps also

[RPGs818SNA]

Alas, all of my five Factory Five supplied coolant hoses leak. It’s a slow leak, and only on non-corrugated side of the hose, so it’s hard to notice, and easy to think they might get better. I tried tightening the clamps, and tightening them with a ratchet, then adding a second clamp on the leaking side, but no luck.

Typical hose that leaks on the right side.
170736

My kit uses 1.75” flexible corrugated tubes and solid 1.5” tubes front to back. My kit supplied five short stiff rubber hoses with a 1.75” inside diameter that gives a snug fit over the corrugated tubes plus a spacer for the smaller tube.

Noticing that none of the Subaru hose connections to the radiator or engine leak, I bought 2006 Impreza upper and lower radiator hoses. The upper hose gave me 2 90 degree bends for the rear plus a 3” straight for the engine. The lower gave me 2 45 degree bends for the front. After cutting off one of the kit hoses, I think I found out what the problem is.

170737

The 3” long stiff hose has a soft rubber interior, a couple of layers of fiber reinforcements, and a final layer of rubber infused fabric that spirals down the outside. The fabric layers overlap, leaving a tiny spiral step along the outside. That’s no problem for the large hose. However, the 1/8” thick spacer hose is built the same way. The soft rubber interior seals against the tube, but the outer hose is not compliant enough to seal the spiral step in the inner spacer hose. So every connection with the spacer had a slow leak, even with 2 clamps tightened way too tight.

Fortunately, after the messy process of cutting off the old hoses and draining the coolant, it was pretty easy to install the new hoses. Using a tiny bit of silicone lubricant in the hose makes them go over the corrugated pipe easily. Note that when I tried to stretch a 12 year old donor hose over the corrugated pipe, I could hear the reinforcing fibers breaking, so I only used new hoses.

Here’s a before and after.
170738

170739

As an extra benefit, the front hoses don’t intrude into the wheel wells anymore, so there’s no risk of the tire rubbing against them. I don’t think there will be any more coolant leaks.
RPG