8 replies to this topic

[Johno]

Just flushed my whole engine with water, replaced water pump and thermo. Engine is 308 stroked to 355 with an original HQ radiator (I think).

I have two questions:

* What coolant and antifreeeze do you recommend? I’m in Canberra so it hits negative zero here. Planning on using a concentrate and topping up with demineralised water.

* Do I need to flush it first with anything to remove any residue of previous coolant? If so, what would you recommend?

Thanks legends!

Edited by Johno, 23 December 2022 - 03:19 AM.

[Uncle Chop Chop]

Yes, flush the old coolant out. I have seen coolant turn to jelly because of the different chemical structures of different brands. Use 100% coolant and just stick to the one brand.

[yel327]

Agree, make sure its properly flushed. Might mean pulling the water pump off to do it properly. I don't use coolant in my HJ, just rust inhibitor. But where you are antifreeze might be a good idea.

 

Note that a 308 strokes to 350ci/5.7L not 355ci/5.8L, of no relevance to your coolant though.

[dron]

+40 stroker is 355, Every kit I have seen runs the +40 pistons unless specialy ordered

 

Any good glycol coolant, Stick to 1 type and no stronger than 50/50 if you go with the concentrate. to strong is not a good thing. Can be just as bad as running nothing at all

Edited by dron, 06 January 2023 - 05:46 PM.

[Uncle Chop Chop]

Why would you want to remove the water pump? Is there an area where the coolant can get trapped and not flush out properly?

[yel327]

I found with my Premier that it wouldn’t flush properly without removing the water pump. Once it was off heaps more cr@p came out, not just old coolant but sludge and crud.

[yel327]

+40 stroker is 355, Every kit I have seen runs the +40 pistons unless specialy ordered

Any good glycol coolant, Stick to 1 type and no stronger than 50/50 if you go with the concentrate. to strong is not a good thing. Can be just as bad as running nothing at all

+40 is actually 357ci. +30 on a standard SBC or Holden 350/5.7 becomes 355ci. But the standard SBC or Holden V8 size is 350ci.

[Uncle Chop Chop]

Tanks for that Yel!

[Johno]

Thanks all, did the flush with water pump removed.