Epic2112

The one on the waterneck, does anyone know the diameter, length, and thread?

Tom M'Guinn

It is an M8 bolt with a 1.0 pitch (not the more common 1.25). It is about 8mm long, with about a 3mm diameter hole down the middle and the same sized hole drilled into one side just under the bolt head -- so that the coolant will vent as soon as the bolt is cracked open. It also has a funky little molded washer on it, to aid sealing no doubt. It's hex head is 12mm across the flats. Mine has a slightly rounded head, so if you end up making one....

Epic2112

Actually, I was thinking about one of these, though I'm not sure it will work.

www.speedbleeder.com

Also, the only M8 X 1.0 bleeder they have is 35.5mm long, although that's the measurement for the whole thing, not just the threaded part that goes in the hole. I may give them a call and see what they have to say about it. I figure that the pressure these have to put up with, and the temps during hard braking, can't be that different from what it would see in the coolant bleeder spot, but I want to run it by them none the less. The stainless steel one is $15, which is fairly reasonable considering how much easier and cleaner bleeding the coolant will be.

Anyone think this is a bad idea?

hosrom_951

Good observation LOL!

Tom M'Guinn

In order for the speed bleeder to open under pressure, you have to loosen it slightly anyway, so I'm not sure how you are better off? Once the system is bled, you'd have to close it like a regular vent bolt, no?

hosrom_951

Note: That speed bleeder is commonly used to replace the bleed screws on the brake system (8 needed).

I don't think that would work because the ball-spring opens/closes (moves up and down) in relation to pressure (brake pedal). In a cooling system, the pressure it pretty much constant (unless really hot and pressure increases), but it wouldn't work (my guess).....

Epic2112

Well, the things that I was thinking about the bleeder are:

1) It needs only a ¼ turn to open, maybe my car is wierd but it seems like it takes a lot of turning to actually open up the vent.

2) Yeah, you'd still need a pressure tester, but you need one anyway.

3) You can put a hose on the end of it, like you would on a brake bleed screw (errrm ) and that way the coolant that is bled doesn't go all over the engine and into all the nooks where it's hard to clean out.

zerMATT951

I was at one of our local Porsche dealers the other day and the parts manager told me that they use the same tool on our cars that Porsche recommends (requires?) to bleed coolant on the Boxster. He said that it's a vacuum device with the proper threads on the end of a hose. I asked him if that adapter was available as a seperate part (his came with the factory bleeding kit), he's going to check.

Simple process - jack up the front of the car, install vacuum bleeder, bleed till you get coolant, cap it. Sounds like a great way to go... I want one of those adapters!

Charlotte944

A Speed Bleeder is not going to work.

Take a look at a brake bleeder and you will see that it is not drilled through, but has a small hole in its side. The end of the bleeder is conical and the port in the caliper is drilled to match so that the bleeder works like a valve. When you back the bleeder out the conical tip comes off of the "seat" in the caliper housing opening the "valve".

Additionally Speed Bleeders have a spring loaded ball check valve that opens with brake pressure.

If you could get a Speed Bleeder to fit the coolant bleed hole you would be blowing coolant all of the time because the conical tip has nothing to seat against.

Epic2112

Ahh, I see what you mean. Thanks Cliff.

Jaak Lepson

An easyest way to bleed the system is use a 8mm grease nipple fitting with the spring and ball bearing removed. Attach a 6 to 8 foot long piece of clear tubing and connect them together with a ty-wrap.


1. Raise the front end of the car.

2. Remove bleed bolt and replace it with the tube/nipple.

3. Place other end of clear hose into the coolant tank.

4. Start engine and turn heater on to full.

5. Run the car until no air bubbles are visable ... hence clear hose!

In some cases the is so much air in the system that it may take up to 45 minutes till air has been removed. If it takes longer .... maybe a HG problem.

6. Replace the Hose/nipple combo with the bolt.

7. Lower car.

Hope this helps. I got this from Rennlist a few years back.

zerMATT951

Jaak - Do you remove the spring/bearing from the nipple to allow the coolant to flow out? I'm going to go searching for a 8mm grease nipple soon... thanks!!

Jaak Lepson

Yup ... sorry ... I forgot to add that part ... unless you can find one without it.

DAR951

... to buy one of these:

http://www.thetoolwarehouse.net/shop/UV-550500.html

This (and similar ones from Mighty-vac, Snap-On, etc.) works great. Get one and forget about jacking up the front and/or any other bleed problems.