Coolant flushing.

[Dave307]

Hi all.
Me again with dumb questions.
Im going to be undertaking my first full service ie sparks, leads, oil, filter, coolant etc. Plus im fitting a full stainless exhaust yay. So my question is 2 fold.

1, I want to flush the coolant system prior to refilling. What flush agent do people recommend or am I better off just shoving a hose up its bottom.

2, having done a reccy of the engine bay looking at the exhaust it is very very rusty. I am therefore guessing that some drilling is going to be required thorough snapped bolts or seized bolts. I have read loads and I'm happy that I know roughly what I'm doing. However if I have to fit studs 10mm do I drill out to 9mm the tap the thread or do I drill 10mm and then tap it. I also saw a picture of an engine cut in 2 which showed the stud depth as being 26mm. Can anyone confirm this.

Thanks in advance.
Just for info as I don't think it shows in my signature I drive a 1986 1.9 dg water cooled.

[Ralf85]

There is advice on the wicki about coolant changing including draining and re-filling.

[kevtherev]

Hi Dave

I also saw a picture of an engine cut in 2 which showed the stud depth as being 26mm. Can anyone confirm this.

I don't think folks cut a WBX head in half ...and take a picture, measurements etc, without confirming accuracy.

1, I want to flush the coolant system prior to refilling. What flush agent do people recommend or am I better off just shoving a hose up its bottom

take a hose off the rad... flush the rad
take a hose off the engine ...flush the engine

with water.

2, having done a reccy of the engine bay looking at the exhaust it is very very rusty. I am therefore guessing that some drilling is going to be required thorough snapped bolts or seized bolts. I have read loads and I'm happy that I know roughly what I'm doing. However if I have to fit studs 10mm do I drill out to 9mm the tap the thread or do I drill 10mm and then tap it.

Studs were fitted as standard.
If you heat the nuts up (red) then nothing will snap
Drill the stud out first (8mm) if it snaps
easier with the engine out IMHO