mattysupra Posted June 25, 2009 Share Posted June 25, 2009 had a quick search but cant find the answer. To cut a long story short, basically im down on compression by 20 psi on number 4. Its also started to smoke like mad on tickover hense compression test along with other tests. All other cylinders are pretty much spot on 170 psi give or take a few psi across the other 5 cylinders. . So i decide to pull the head off and have a better look! On stripping down the turbo side i was met by red dust all over the turbos and water lines and over the head around cylinder 4 (the one thats down on compression) What the hell is the red dust? Is it rust that has come adrift from the manifold maybe from heat? Im thinking maybe number 4 has gone lean and caused massive heat maybe as it seems located to this cylinder? Your thoughts please, cheers matt. Quote Link to comment Share on other sites More sharing options...
bluecoup Posted June 25, 2009 Share Posted June 25, 2009 small hole in a water line spraying mist which has rusted ? Quote Link to comment Share on other sites More sharing options...
Homer Posted June 25, 2009 Share Posted June 25, 2009 The red dust will be metal oxidisation or dried "toyota red" coolant if it was old. Plenty of causes for what you've described, is the red on the turbo on the exducer or compressor side? Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 25, 2009 Author Share Posted June 25, 2009 nope, never lossed a drip of water, and to be fair its always run on toyota long life stuff that came out very clean. All the bits on the car was chromed afew years ago and are still shinny even on the insides, no rust in the water system at all. The engine was rebuilt less than 20k miles ago also, most of it is HKS internals. Cant belive its dropped compression on 1 cylinder as it is. It has however sat for a year but has been started evryday and moved in and out of a unit. It did manage to get a missfire, i never knew about this untill a few weeks after it started as nobody decided to tell me. Only found out when i turned up and the car was being moved and i heard it when i pulled up. I dont know which cylinder the missfire was on as i just got on and changed the plugs which fixed the problem, however this smoke problem started just after. As i only see the car run once every month im going off what im told. Something has gone wrong at some point and as the guy who moves the car every day dont have a clue i dont know when it went wrong! Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 25, 2009 Author Share Posted June 25, 2009 sorry homer, posted the same time! You talk about coolant also, i will have to double check tommorrow. The red dust is on the exhaust side of the turbos and up the back of the cool side of the rear turbo but also all over the head around cylinder 4. It is also all over the water line running over the top of the turbos. Maybe i have a crack in the turbo housing where the water is? Maybe this happened on last track day when super hot? Maybe the water pipe is leaking but it looks perfect, better than perfect! And yes its running the red toyota coolant! Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 25, 2009 Author Share Posted June 25, 2009 you can see the dust in the picture, i had wiped the water pipe and alot off with my hand before i took the pic. Where circled you can see it on the head and around the rear turbo. It does however look like its located around where the water pipe is connected but it goes down and under it a bit also! Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 25, 2009 Author Share Posted June 25, 2009 anyone else got anything to add or are we going with coolant leek? Quote Link to comment Share on other sites More sharing options...
CWD Posted June 26, 2009 Share Posted June 26, 2009 as above looks like coolant residue, if you are down on compression it maybe a head gasket, have you had a proper compression and leakdown test done? it doesnt take a big leak to leave lots of evidence behind Quote Link to comment Share on other sites More sharing options...
Paul Whiffin Posted June 26, 2009 Share Posted June 26, 2009 Did you do a leak down test as well as compression test? Quote Link to comment Share on other sites More sharing options...
little num Posted June 26, 2009 Share Posted June 26, 2009 id also say head gasket on cyl 4, and thats where the coolent is leaking from, did you look at the spark plug you took from that cylinder to see if that had red on as well. Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 26, 2009 Author Share Posted June 26, 2009 no leak down test done, broken gauge and also my compression tester broke on re checking! Plugs was all looking fine. Im half way through taken the head off so i guess things will become clear when i have it off. Cheers for the replies. Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 28, 2009 Author Share Posted June 28, 2009 update! The heads off, the valves all look like new apart from the two exhaust on number 4 cylinder, they are well coked up and wet looking. They was not sealing very well so i guess this is why it was down on compression. I guess the valve seals must be knackered on this cylinder and thats whats coked them up along with the miss fire it had. However, this red dust! It seems to be coming out of one of the plugs with the allen key in the center that run along the length of the head. I guess they lead to the water jacket? What are these for? some kind of core plug? For cleaning the water jacket on rebuilds? Whats behind them and how do they seal? I dont want to remove one untill i know what they are for! Thanks. Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted June 28, 2009 Share Posted June 28, 2009 Are you sure it's not the head gasket thats leaked into the cylinder, then when the piston has tried to compress the uncompressable coolant, it leaks out the side where the red dust is.? Quote Link to comment Share on other sites More sharing options...
Suprash Posted June 29, 2009 Share Posted June 29, 2009 What exactly is involved in doing a leak down test ? Quote Link to comment Share on other sites More sharing options...
bondango Posted June 29, 2009 Share Posted June 29, 2009 a Cylinder leak down tester.. Basically turn Cylinder to Compression Stroke, Add compressed air via a leak down tester tool. If your valves are leaking the air will escape into the exhaust or intake, if its the rings, down into the sump. The tool will show your the percentage of air loss as well. Listening to the exhaust pipe, dip stick tube, or into the TB during this gives you the culprit. Coolant leak down.. During this test, you apply Pressure to the coolant system via the radiator using a special adpater cap. The system should hold 0.9bar of pressure. If you have any leaks the system will not hold pressure, and the leaks will also be visible if they are coolant hoses etc etc, Unless they are internal i.e. headgasket. If they are internal, then next thing to do is check the oil for emulsion and do a coolant sniff test Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 29, 2009 Author Share Posted June 29, 2009 Are you sure it's not the head gasket thats leaked into the cylinder, then when the piston has tried to compress the uncompressable coolant, it leaks out the side where the red dust is.? No not the head gasket. The red dust had gathered above the headgasket and behind exhaust gasket where one of these plug things are. There is no way it could of come from the headgasket as all the red dust is above the exhaust manifold rather below it where the head gasket is. Can someone confirm what the plugs with the allen key in the center are for please! Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 29, 2009 Share Posted June 29, 2009 They are core plugs. I don't know that much about them apart from they are important If you've got coolant leaking from them I can't help but think it's a sign of a serious problem. They shouldn't come undone, so I think a cracked block is the only way it could be leaking from that area but I could be wrong. -Ian Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted June 29, 2009 Share Posted June 29, 2009 If it's leaking really bad, and you can't live with it. Is it worth removing the plug, then covering the thread with PTFE tape and re-fitting.? Quote Link to comment Share on other sites More sharing options...
mattysupra Posted June 30, 2009 Author Share Posted June 30, 2009 its not leaking bad at all. I didnt know it was leaking untill i took the heat sheild off and found this red powder. Im presuming its coolant that has leaked and caused the red dust as i have been adviced on this thread. I was thinking it was rust of the manifold but never seen before. As the head is off the car at the moment i would like to find out what has caused it and fix the problem if it is a leek before it gets worse. Quote Link to comment Share on other sites More sharing options...
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