Author Topic: Strange noise after overheating and almost freezing (Read 4580 times)

bvolks73 · « **on:** February 09, 2007, 09:03:45 pm »

My 85 Jetta has been having some overheating problems for the last couple weeks and the other day it overheated really bad on me and pumped out a lot of it's antifreeze. I let it cool down for an hour or so and then topped it up with some water to get me home. I had to run into town to license my 89 GLI (and grab a jug of antifreeze) since I knew the diesel was going to be down for a while so I just plugged it in to keep it from freezing until I got back (the temperature was down around -23 C). However, the block heater cord gave out on me while I was gone and when I got back later on the "antifreeze" was a hard slush. I thawed everything out with warm water, blew everything out and took the rad and all the hoses off and brought them inside. I'm quite sure everything got drained pretty well. I fixed the block heater cord and put everything back together today (with new antifreeze this time) but it's making a terrible noise when it's running. Sounds to be coming from the top of the motor near #1 cylinder. I pulled the alternator belt to rule out the alternator or water pump being the culprit but the noise is still there. Pulled the timing belt cover to see if anything was hitting under there but nothing. It sounds like something is pounding against the valve cover from the inside. It also sounds like an exhaust leak coming from the head that was never there before. I could see a cracked head from the overheating causing the exhaust leak but not the rattling sound. It sounded absolutely normal when I drove it home after overheating it. I found the return line from the radiator was plugged solid and I think that why it was overheating in the first place because it happened before. Any ideas? The fuel economy I'm getting with the GLI is driving me nuts.

burn_your_money · « **Reply #1 on:** February 09, 2007, 09:13:47 pm »

how does it run otherwise? is it really rough?

bvolks73 · « **Reply #2 on:** February 09, 2007, 09:25:32 pm »

It actually runs ok. Starts up and revs fine. I've only let it run for a minute or 2 since I'm scared of doing some real damage if it hasn't happened already. I wish there was a way to post a sound clip.

burn_your_money · « **Reply #3 on:** February 09, 2007, 09:42:48 pm »

youtube.com or google video

jtanguay · « **Reply #4 on:** February 10, 2007, 01:21:32 am »

my car overheated... lost all the coolant... and one of my valves was flapping

the car ran and drove great for just under a year, and cold starting was pretty easy too... very weird!

bvolks73 · « **Reply #5 on:** February 10, 2007, 07:11:37 am »

If it was just something in the head making the noise I could live with that since I have a spare head stashed away here somewhere. Will a 85 head work on an 84 block with no problems? I'm pretty sure they didn't have hydraulic lifters in 85.

jtanguay · « **Reply #6 on:** February 10, 2007, 07:22:12 am »

i had an '86 with mechanical lifters... midway through that year they started producing the hydraulic lifter engines.

i prefer mechanical lifters, but hydraulic are easier to maintain.

bvolks73 · « **Reply #7 on:** February 10, 2007, 04:04:56 pm »

Found the problem. The noise was valves and pistons colliding. I noticed the belt seemed loose when I had it running with the cover off so I checked the timing. The cam was out by the equivalent of one tooth on the belt. I don't see any missing teeth on the belt so I'm wondering if the keyway on the end of the crank might be worn and the timing gear might have moved. Anyway, I put it all together and it sounds like it always did. No strange noises at all. I assume the "exhaust leak" I thought I heard must have been the valves and pistons colliding. I took it for a short test drive (10 miles or so) and it doesn't seem any different than before and it's not overheating, even when i wound it up to 140 or so. Still, I'm going to get my spare head rebuilt just in case. Now to get the heater core that blew when it overheated the first time replaced. (I just bypassed it for now but no heat in -20 weather is no fun).

burn_your_money · « **Reply #8 on:** February 10, 2007, 04:42:49 pm »

I hope you put a new belt on there. You're lucky it still runs

bvolks73 · « **Reply #9 on:** February 25, 2007, 09:37:26 am »

I've put 1000 or so kms on it since it's ordeal and it seems to be a bit harder on fuel than before. I think it's time to pull the head and check for bent valves. I read that you can put a TD head on a NA block without a lot of problems as long as you keep the NA pump. Apparently it works like an ecodiesel. Is this true? I have a solid lifter TD Rabbit head and the exhaust downpipe (and 4 complete TD engines for parts for anything else I might need) already so I figured if I'm going to pull the head I might as well put that one on if it's possible and won't drastically shorten the life of my motor. http://www.vwdieselparts.com/forum/viewtopic.php?t=6302