Shop vac flush works!
Thread Starter
Safety Car
Joined: Mar 2017
Posts: 4,194
Likes: 1,317
From: LeClaire Iowa
Shop vac flush works!
I tried the shop vac cooling flush today. It was easy as I had my radiator out for changing my two cooling fans. Yes, two years ago I pulled the knock sensors. I am 67 with no lift and that is a problem for me to do. I had some brown floating stuff I wanted to flush out. I took out the thermostat and used the gasket to bolt the housing back on. I taped my shop vac to the top radiator hose. I put the radiator cap on and plugged that little hose that goes to the top right of the radiator (1996). I then turned on the shop vac and blew a lot of water out. I would then refill through the radiator cap until it drained out the bottom hose. Then blew the shop vac again. I did this 20 times and the water being blown out was perfectly clear at the end. You could leave the bottom hose on the radiator and just drain out the radiator drain. After blowing out all the water I could I measured how much water I had to add to get it to gravity drain again and it took 1-3/8 Gallon. So each time I ran the shop vac I was flushing 1-3/8 Gallon from the bottom end. Attached is a youtube video early on when the water being blown out was not clear yet.
Thread Starter
Safety Car
Joined: Mar 2017
Posts: 4,194
Likes: 1,317
From: LeClaire Iowa
Thanks. The first blow out I was able to catch in a drain pan and it looked bad even though I flushed a year ago (with knock sensors). Lots of the floating brown stuff. At the end the water I caught looked clear enough to drink. I maybe did it even 25 times. Each time only takes 3 minutes to fill up and blow out. Without the video it does not seem like it would work as well as it does. It would take a lot longer if the bottom radiator hose was left connected because, as seen in the video, water comes out fast, much faster than the little radiator drain can handle. I think the agitation of the water and air help to clean the bottom out better than just letting it gravity drain out the knock sensors. I looked at the flow diagram and this method should flush the heater core (not 100% positive).
Thread Starter
Safety Car
Joined: Mar 2017
Posts: 4,194
Likes: 1,317
From: LeClaire Iowa
Thank you for the kind words. Some updates: I don't think this system actually flushes the heater core and it can be flushed separately very easily. I had my radiator out which makes it easier. Again, the radiator would need to be flushed separately. I also don't think that flushing through the radiator drain is viable as you need and want that vigorish movement of the flushing water in the block. Since each cycle is very fast I suggest doing it many times until when you catch the water it is perfectly clear. Catch the first flush and the gunk will amaze you. It has to affect heat transfer. It sure helps to have a gravel driveway but if you drain all the coolant you can into a container and do the first flush without adding any fresh water in the pressure tank you will have 95% of the coolant out and later flushes should not hurt any animals. Dan
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