Hi guys, One day coming off the freeway I noticed my temp gauge fluctuating up and down and when I got home noticed a lot of steam out the exhaust. Code read cylinder 3 misfire, removed the sparkplug and water shot out the cylinder. Thought the head gasket was blown and parked the car. Bought the car recently and only had water in the system not coolant.. Anyway the water was low and there was also gunk in the walls of the reservoir, oil/greese. No water was mixed with oil on dipstick. I pulled the head off and the head gasket is fine and no signs of head/block issues, head bolts were also tight. Havnt had the head pressure tested yet, but does anyone else know what the issue could be? Could the turbo be pushing water into the intake? Motor has done 80, 000 km stock and looks in decent shape. Thanks, any advice would be greatly helpful.
Check the combustion chamber for cracks between the valve seats, its getting to be a common issue on mk3 rs. Was it misfiring on cold start? Mine was misfiring from cold for 5 seconds as coolant was weeping into cylinder 1 when engine was switched off. Still made 360hp on the dyno when poorly.
Thanks Brigsy, yes exactly that, was misfiring/rough idle on start up for a week leading up to seeing the steam out the exhaust, thought it was down to plugs needing to be changed, but obviously not. Was running normal at higher revs. I guess that's comforting to know, I've been stumped as to what the issue is, visibly can't see any cracks but haven't taken the valves out yet. I'll be sending the head in for pressure testing as soon as shops open after Xmas. Thanks for the insight!
This is a pic of the issue that Alex White (AW motorworks) sent me. Cracks between valves and the coolant drops into the cylinders. To fix its valves out, valve guides removed, welded and machined then refit.
Thanks so much for this Brigsy, I went and scrutinized mine with a torch and I found exactly the same, a crack between the two valves! I'm so relieved I now know what it is and didn't strip everything for nothing! Thanks for your assistance!
Good to hear you have found the issue. Any pics of the crack for comparison? I need to strip mine at the weekend will see if its the same.
Hi Brigsy, no it's completely stock. I'm regards to a pic, unfortunately sent the head in for them to assess, however it was in the exact same place as the pic you sent, just was a lot harder to see on mine, almost needed a magnifying glass. I'm. Interested to know if the pic you sent had cracks between all the valves, or if they were all just done as reinforcement. I'm contemplating purchasing a used head instead of getting it repaired, what are your thoughts? Price would be around the same, maybe slightly more expensive
I think the one in the pics had cracks between all the valves. If you can find a good used cylinder head that will be ok. Quite hard to find though.
Do you know if this is this caused by poor design from Renault? Or is it more to it like manufacturing date of the engine or maybe something else. How much did it cost to sort out?
I managed to find a used head thankfully and sent it in for a recondition, they let me know today that it's ready
Hi Brigsy, I'll likely have to start another thread but have you had any issues when purchasing head bolts. I have ordered from two different companies and they keep sending me bolts for the f4r 730 and not f4r 874. The bolts are not as thick on the head. Aftermarket on the left and original on the right. Have you experienced anything like this? Original from Renault are just Ludacris in price.
Aftermarket parts issues i guess. I think they will be ok, im sure mine is/was running normal 225 head bolts with 250 head. Whats price on oem? Ive used arp head studs on my new build but they are also pricey.
Thanks Brigsy, that's comforting to know. They wanted around $220 at Renault, I couldn't bring myself to spend that on bolts!
HI there, Can I get a bit of advice on the cylinder head tightening please. Maybe I'm not understanding.. So I stared tightening 1-10 from inside out all to 30nm, then I did another round of tightening to 30nm again. Then I started doing number 1 and 2 to 180 degrees which was tight. By the time I got to bolt 3 the bolt was completely loose and got to 180 degrees with not much effort and it didn't feel that tight. Am I doing something wrong?
Legend for responding so quickly!! How long would you say between each stage? So I was doing it correctly though? Thanks Brigsy!
