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Motor ruined? by Henchman on 22 Jul, 2010 16:33
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So, I may have cooked my AAZ motor today. I noticed after my drive to work that I was loosing coolant. I added about 5l of water and then realised that the nipple that the connects the coolant return line to the overflow bottle was broken and leaking. So I reconnected the hose to the remainder of the nipple and drove home. About 45 mins into the drive I noticed the strong smell of coolant followed by a hot engine smell. Turn off the engine, and coast for about 1km and stopped on the side of the highway. Popped the hood, and the engine is hot, really hot. Water sizzling off the camshaft cover. Adding water to the overflow immediately steamed out of the head coolant manifold, which had partially melted and caused an even bigger leak. This means the head ran dry for at least some period of time.
So I added as much water as possible, cooled the engine with water slowly and dragged the car home on my dolly. It's cooled off now. When I try and start it the engine doesn't spin very fast, even when boosting from another vehicle. The starter gets hot. The only hope I have is in changing the starter, because it was a gas starter (the car was a diesel convert), so the starter was kind of lazy to begin with. Failing that, I'm gonna assume the engine is pooched. It was running when I shut it down after noticing the smell, and it just got an oil change 2 days ago with synth 5w40.
Any thoughts? If the starter change doesn't make a difference, I'm going to pull my spare AAZ out of my other passat and transplant.
In retrospect I would of.....
Ian -
#1 by Smokey Eddy on 22 Jul, 2010 16:50
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Your synthetic oil may have saved you if it had moly in it.
What i would do is drain all the oil out of it right now and let it drain for some time. Get as much out as possible and put in some freshy.
take off the vacuum pump and stick a 12mm deep socket on the shaft you see sticking up. It drives the oil pump. Spin this shaft with a drill if you can. You should see oil come up and show near your socket.
do this for at LEAST 60 seconds.
now try turning the engine over with a ratchet. 19mm 12pt on the crankshaft.
You should feel some hefty resistance followed by an easy 45 degrees or so then hard then soft and so on.
if it's too difficult to turn by hand you may be looking at some other issues.
While it was over heating was there a buzzer going off? did you oil light flash? If the answer is NO to both of these questions i suspect some fresh oil will perhaps save your day.
Most often what happens with a really bad over heat is the alluminium cylinder head will warp and lift and you'll have a coolant/oil leak between the head and block. The compresion will be greatly reduced resulting in FAST turning and very poor starts.
Check that it turns over easily first, if so replace oil & leaking coolant parts.
If it does seem overly difficult to turn as in you either CANT turn it with a 1/2" ratchet or you need a huge breaker bar to do it report back here
it SHOULD be tough to turn as these engines produce huge compression (you'll hear it hissing when you turn it over)
hope this helps some.
worst case scenario so you have an idea is you cooked the oil, it didn't lubricate and the bearings siezed on the crank. But it takes some extremely abuse to do that. The cylidner head - worst case scenario it warped from the heat and you can remove it and have the surfaced "decked" at a machine shop - take a few ten thousandths of an inch off until it's perfectly flat again. -
#2 by GEE-BEE on 22 Jul, 2010 17:31
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Another bad hose problem, I hope you change out your next set with silicone type with the correct clamp's
Been there , done that
Good luck, I would still tear down and inspect the head...
GB -
#3 by jpedro on 22 Jul, 2010 17:36
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what are the tollerances for a warped head? mine was about 6 thou out and sent it away to get fixed.
i have an extra head with no valves cause i broke a timming belt but have new ones for it. do you need to replace the guides after valves hitting or just the valves and a valve grind be ok? if so i might do that to get it back on the road in the meantime, cause this head deck is taking the shop sometime to do. was sent outta town. -
#4 by Smokey Eddy on 22 Jul, 2010 21:27
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Hard to say. If the new valve slides into the guide freely i'd run it. but then again... i have a bad track record with engines blowing up ^.^
if the valves bent badly they would have deformed the guide causing the new valves to not move freely.
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#5 by Henchman on 27 Jul, 2010 14:26
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So, after changing out the starter, disconnecting all the accessories, the engine still turned over very slowly, so lots of internal resistance, engine shot.
No problem, I have my 93 Passat AAZ parked 15 in front, so Saturday and Sunday I pull the bad assembly out of the wagon, pull the good assembly out of the 93, reinstall in the wagon. Before I put the front clip and stuff back on I decide to start it up. Had a hard time getting started (this was my daily until 2 weeks earlier), realized that because I hadn't hooked the cold start lever back up, the lever on the pump was way forward. Push it back, couple of cranks and it starts, but sounds REALLY bad, after a second, I shut it down and try to restart. Sounds very funny. Pull the timing cover, belt snapped! Couldn't believe it! I had done a timing belt on it last fall.
So Sunday afternoon, replacement engine in and I don't know if I've just ruined another. Took the day off of it yesterday (had to work on other peoples cars) and replaced the timing belt today. As soon as I got the lower cover off, the cause was obvious. A metal grommet off the upper cover that sits in the center outside, had somehow fallen inside the timing covers (probably during the removal/install) and cause the belt to snap. Replaced the belt and it started right up. Sounds like a bag of hammers, but that's OK because it sounded like that before! Let it warm up, sounds OK so tomorrow I'll put the clip back on, reattach the exhaust and hopefully not have to go through this for a while.
Ian -
#6 by Smokey Eddy on 27 Jul, 2010 17:03
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Did you actually turn it over by hand?
it makes a huge difference if you turned it over by hand or not...
It would be a sad tale if you junked an engine because it had really good compression and a weak starter that couldn't do it. -
#7 by Smokey Eddy on 28 Jul, 2010 13:52
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So, after changing out the starter, disconnecting all the accessories, the engine still turned over very slowly, so lots of internal resistance, engine shot.
i REALLY want to know if you primed the oil pump before you turned it over and if you turned it over with a starter or with a ratchet... -
#8 by Henchman on 30 Sep, 2010 19:02
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So I know it's been a while, but I thought I would update on what I found when I opened up the engine. There was coolant and coolant residue in the combustion chambers and into the exhaust manifold. It appears that the engine overheated as a result of loosing coolant to the point of no longer being able to circulate it around the engine, which caused the head to warp, which caused head gasket failure, allowing what coolant was left into the combustion chambers. So engine was proper pooched.
Anyways, old power unit out of my 93 has been working better than ever since, now with 400k km.
Ian