Topic

Hi all,

hopefully my last question on the subject of head gasket changes...

HGF on my TF has led to the mixing of oil and coolant both ways, coolant was drained at the beginning of the job but has the obvious emulsification throughout the engine/cooling system! oil isn't too bad but still a little milky...

Once the HG change is done and everything re-assembled, do I run the engine up to temp with just water then run it with a coolant flush solution before draining again and replacing with proper coolant? if so what coolant do I need for the final refill?

And, should I run it with oil flush in the existing scummy oil before replacing it with fresh oil/filter?

Cheers

Andy

Both suggestions are good.

With coolant, drain as much as possible first, then fill with water and a couple of dishwasher tablets for a short while (few hundred miles) then thoroughly drain whole system, as best you can, then re-fill with OAT antifreeze.

Oil, again drain as much as possible, and re-fill with cheap oil (some suggest diesel rated) and run for a short while to fully circulate and warm up. Half hour or so.
Then drain down and fill with correct quality oil, not forgetting oil filter.

Should be OK after that.

Thanks G0RSQ...

Never thought of the dishwasher tabs as a degreaser... would you suggest just adding these to the expansion tank?

thanks again!

Andy

YES, Just crush up the Dish washer tablets and put them into the expansion tank, use a good quality tablet

Hi all,

Looking for a bit of re-assurance as I'm currently suffering from the post HG change coolant paranoia...

As recommended, I put a couple of dishwasher tabs into the expansion tank to help flush the system...

Car starts and runs sweet as a nut, oil temp rises to about the 90 mark and coolant temp sits steady with the needle a little below half way, the heater runs well and there's no sign of any venting from the cap.

This morning before a short trip to the shops I checked the level in the expansion tank which was a little low, but I reckon this is to be expected as a bit will boil off being only water so I added about half a pint just to bring it up...

However, the contents of the expansion tank are black... not emulsified, but clearly looking like old oil with that oily texture (pretty much the same colour as what I drained before changing the gasket)... engine oil level has not dropped since I changed the oil on Saturday.

Would it be fair to say that these black contents are most likely the remains of the contaminants that were in the system before I started and this is simply a case of drain, refill, bleed over and over until its clean and ready for a final fill with OAT?

Thanks in advance...

Andy

When the HG failed in my R400 it took at least three flushes to clear it completely and that was using an industrial cleaner gor flushing coolant systems, so don't fret just yet gi e it another flush, reverse flush wherever you can too it helps.

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Dishwasher tablets are pretty fierce and will dislodge pretty well everything in the system. I don't like them because adding strong alkalis to alloys never ends well. I expect that you have cleared out all the silt from the radiator and the heater matrix and that is what you have in the header tank. Syphon it out, drain the rest of the system, refill it, adding a tablespoonful of vinegar and drain it again once the engine has been warmed up