Coolant Leaking from ACSD?

Joined
May 18, 2007
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New Zealand
I walked outside to find a small pool of radiator coolant under my vehicle yesterday (much to my disgust as I've just replaced the radiator due to a leak in the core last month and triple checked all my hose connections). It appears that green coolant is possibly leaking from the ACSD (Assist Cold Start Device - or sumfing lyk dat!). Looking closer under the hood there appears to be green coolant over the side of the Injector pump below the ACSD line and on the ACSD spring. Looking around there doesn't appear to be any water pipes in that area besides the ones going into the ACSD and the water seems like it's not leaking from the pipe inlets/hose connections themselves. So I'm wondering if water can possibly leak from somewhere else on the ACSD or thermowax housing?
Has anyone ever taken one of these apart or know if a part of them is prone to leaking, and if so can it be fixed? I couldn't find much info on what parts are inside the ACSD but after reading some posts on Mud I'm actually thinking about taking the ACSD out altogether and sealing up the inlet on the injector pump to fix the problem. But I just thought I'd check if there was a fix first before removing the ACSD altogether, as most people have removed theirs based on idling issues and I don't seem to be experiencing that......
 
Joined
Sep 29, 2004
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San Francisco, CA
pretty easy to pull it off, but seems like the problem is more likely to be hoses than the acsd itself.

you mention coolant on the spring- could it be spraying out from a pinhole in the hose?

first step may be to replace the hoses. 3/8" ID should do the trick. If that doesn't fix it, pull the acsd and run a hose from top to bottom on the block. Done.
 
Joined
May 18, 2007
Messages
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Location
New Zealand
seems like the problem is more likely to be hoses than the acsd itself.

I had another look today and I definately think the coolant is running out the front of the acsd - rather than the back of it where the hoses enter it. On the front of the acsd there is a little black rubber looking thing which pushes the arm when the thermowax heats/cools. There definately appears to be water tracking from that little black rubber bit and it's pooling on the bracket in front of it, then dripping onto the acsd spring and then down out the bottom onto the ground. There is no water tracking on the hoses or around the back of the acsd at all....
Has anyone ever taken a acsd apart and know how the water makes it's path around in it or what parts are actually inside it? Im wondering if that little black rubber thing has some kind of seal or something which has worn allowing water to escape??
 
Joined
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I just pulled my acsd- if I were in your shoes I would yank it, put a blocking plate, and be done.

the acsd does have a circlip that appears to hold the body of it together. After pulling the plunger out, and also pulling the circlip, I still couldn't take it apart. I gave up (other jobs calling) but IMO there is no good reason to rebuild it unless you regularly start your rig in very cold weather (well below freezing).
 
Joined
Jan 29, 2009
Messages
27
Location
Canberra, Oz
.....Has anyone ever taken a acsd apart and know how the water makes it's path around in it or what parts are actually inside it? Im wondering if that little black rubber thing has some kind of seal or something which has worn allowing water to escape??
The ACSD is just a wax pellet canister with a rod sticking out one end. The 'canister' is sealed to the ACSD by the use of an O-ring and of course there are the inlet and outlet connections on the ACSD too. The water flow is basic with no guides. The wax canister can be removed from the ACSD housing by hammering it out by sticking a small rod down the coolant connections, but there's a good chance the rod will damage the ACSD housing wall so it becomes a bit hit and miss. Might have a wax canister out in the garage somewhere. If I find it I'll post a pic of it and the damage that gets done to it when its removed.
 
Joined
Jan 29, 2009
Messages
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Canberra, Oz
..... Might have a wax canister out in the garage somewhere. If I find it I'll post a pic of it and the damage that gets done to it when its removed.
OK attached are some photos for interest sake.
The O-ring dimensions are; OD=29mm, thickness 3.5-4mm.
The wax pellet thingy has an outside diameter of 28mm.











Removal damage




 
Joined
May 18, 2007
Messages
16
Location
New Zealand
hey hdjeighty thanks for the very detailed pics! Sometimes seeing is understanding. :cheers: So it seems that if coolant is coming out the front of the unit the o-ring is failing as it appears that is the only place it can come from, unless of course its somehow penetrating the wax pellet itself and coming though the front of it where the plunger pin goes in (if that's possible?). If it was just the o-ring I guess it would be a pretty easy fix but as you say the trick would be getting it out without damaging it!?
If it's just an o-ring, then perhaps I'll try fixing it first just incase Global warming really is true and climate change means I'll need it sometime in the future :D:D At the end of the day if I fail I can just block it off.
If you or anyone else for that matter has any wise after thoughts on a better way of how to get the pellet out of the housing without damaging it I'm all ears.......
 
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