Martin White Posted February 5, 2021 Report Share Posted February 5, 2021 Hi All Just a quick question regarding oil flush after replacing cylinder head. Am I best to flush through with cheap oil (start engine get it warmish, drop the oil and replace again) and do I change the oil filter when I put the last lot of oil in Thanks Link to comment Share on other sites More sharing options...
johny Posted February 5, 2021 Report Share Posted February 5, 2021 Can I ask what work was done on the head? Normally flushing is recommended after crankshaft machining and rebores.... Link to comment Share on other sites More sharing options...
Clive Posted February 5, 2021 Report Share Posted February 5, 2021 Did you get water etc into the oilways? If you want to flush I would put the cheap oil in, and actually get the car driven for a while so it gets properly hot and circulates for plenty of time. Then dran and fill with your oil of choice and change the filter If you have been careful and not got anything into the oilways, I wouldn't worry about an oil flush. Even a bit of coolant isn't a real issue, it soon evaporates Link to comment Share on other sites More sharing options...
Martin White Posted February 5, 2021 Author Report Share Posted February 5, 2021 Hi Clive/Johnny Blown head gasket so yes water in the oil. Probably due to blocked waterways which has now been resolved. Heads skimmed and ready to go back on. Martin Link to comment Share on other sites More sharing options...
johny Posted February 5, 2021 Report Share Posted February 5, 2021 I personally would go for normal oil, let the filter do its job and burn the money saved driving the car☺️ Link to comment Share on other sites More sharing options...
Martin White Posted February 5, 2021 Author Report Share Posted February 5, 2021 OK Just so I understand correctly Drain and change oil and filter. Run as normal and don't redrain oil Thanks Martin Link to comment Share on other sites More sharing options...
dougbgt6 Posted February 5, 2021 Report Share Posted February 5, 2021 No, what Clive said! After I fixed mine I ran for a couple of weeks on Halford’s classic 20/50 and then swapped over to Millers. My next door neighbour asked “How do you know it’s blown a head gasket?” (Doh!). I turned the engine over and a jet of water shot out No.1 spark plug hole. Missed him, sadly. Doug 1 Link to comment Share on other sites More sharing options...
johny Posted February 5, 2021 Report Share Posted February 5, 2021 Yes perhaps it would be best to drain the exisitng oil (if you havent already) without getting it hot as it could be quite contaminated from the head gasket fail. Then just a normal oil + filter change and run. Then you can check the colour of the oil to ensure youve not got any water in it (milky colour) and if ok drive it until the next usual oil change... Link to comment Share on other sites More sharing options...
Martin White Posted February 5, 2021 Author Report Share Posted February 5, 2021 Great thank you Johnny. Saved £20 quid on a further oil change and filter. Link to comment Share on other sites More sharing options...
johny Posted February 5, 2021 Report Share Posted February 5, 2021 Yes I would do an flush change if moving parts had to bed in after machining as that will tend to generate metal particles. Im guessing that the original blocked waterway was probably down to poor maintenance and I hope that didnt happen during your custody of the vehicle😁 Link to comment Share on other sites More sharing options...
Martin White Posted February 5, 2021 Author Report Share Posted February 5, 2021 No. I am slowly putting things right after buying. Managed 10 miles before head gasket blew. Has been a god send during lockdown though as given me plenty to do and still plenty left to do. Hoping to get it up and running reliably in time for nice weather and club meets etc 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 5, 2021 Report Share Posted February 5, 2021 1 hour ago, clive said: I wouldn't worry about an oil flush. Even a bit of coolant isn't a real issue, it i agree with Clive , its quite rare that any coolant gets into the sump oil with a HG failure in general it doesnt migrate past the rings and most HG failures allow high combustion pressures into the water jacket not the few psi of the coolant untill you stop and then it may entre the bores , rarely into the tappet chest Pete Link to comment Share on other sites More sharing options...
Martin White Posted February 5, 2021 Author Report Share Posted February 5, 2021 Thanks all Link to comment Share on other sites More sharing options...
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