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| | | tick tick tick | Joined: Dec 2000 Posts: 3,750 Likes: 13 | OP Joined: Dec 2000 Posts: 3,750 Likes: 13 | so the astro has what sounds like an exhaust leak... ticking sound, but only under load. start it up and let it idle, no noise at all. I thought it might be the doughnut gasket between the headers and the y-pipe (yes, I have headers), but I can't see it/feel it when I check. hoping it isn't the manifold/header gasket, but hard to tell since I can't put the engine under load while I'm under it. 90 Astro - "The Grey Ghost" - Haulin Ass, Not kids.E-Z Vanners and West Vanners Council of Councils Board Member National Truck-in Board Support Team "No matter where you go, there you are." "If you can't do something smart, Do something right" "There are three kinds of people in the world, those who can count, and those who can't"
| | | Re: tick tick tick | Joined: Apr 2010 Posts: 2,847 Likes: 42 veteran | veteran Joined: Apr 2010 Posts: 2,847 Likes: 42 | Not an engine pro but the exhaust leak ticks are usually when cold and go away once warm, and are there in the presence of load or not.
A ticking under load when hot could be internal engine issues, and a mechanics stethoscope can be beneficial in diagnosis.
I had a '73 Holden Kingswood in Australia which was ticking, same inline 6 engine as GM's of that era. I brought it into a mechanic and the ticking did not get louder under load and the guy was like its fine. That was in West Australia, and I drove it across the Nullabor Plain and sold it in Sydney some 9 months later.
Some say Marvel mystery oil in the sump eliminates ticky lifters. Some say thicker oil, some say thinner. Some think an italian tune up is the call. | | | Re: tick tick tick | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 | Marvel Mystery Oil has always worked well for me in freeing up sticky lifters. It is the only oil additive I will use. Thicker oil has a harder time getting into small spaces, so I don’t recommend it if your motor has problems.
Have you elimnated spark knock/preignition as a possible cause of the noise?
Windows- they're what make a van worth owning! | | | Re: tick tick tick | Joined: Dec 2000 Posts: 3,750 Likes: 13 | OP Joined: Dec 2000 Posts: 3,750 Likes: 13 | Marvel Mystery Oil has always worked well for me in freeing up sticky lifters. It is the only oil additive I will use. Thicker oil has a harder time getting into small spaces, so I don’t recommend it if your motor has problems. I just did a fresh oil change with full synthetic, haven't added anything to it though. Have you eliminated spark knock/preignition as a possible cause of the noise? how do I do that? 90 Astro - "The Grey Ghost" - Haulin Ass, Not kids.E-Z Vanners and West Vanners Council of Councils Board Member National Truck-in Board Support Team "No matter where you go, there you are." "If you can't do something smart, Do something right" "There are three kinds of people in the world, those who can count, and those who can't"
| | | Re: tick tick tick | Joined: Aug 2001 Posts: 12,107 Likes: 37 Maniac | Maniac Joined: Aug 2001 Posts: 12,107 Likes: 37 | I don't know much about Chevies. If the Astro ha a distributor, you can try turning it to retard the timing a bit. If it is a distributorless ignition system then I don't have a clue.
On my Ford I recently eliminated a noise that had been bothering me since I swapped engines back in 2010. On hard acceleration, an especially when turning right and accelerating, I would get a very loud "BBURRRRRRRR" noise from under the doghouse. I checked everything I could think of that might make the noise. It turns out the passenger side exhaust piper flange was not fully seating on the manifold and would leak only on hard acceleration or right turns. At idle there was no sign of a leak, and even revving it in park or neutral it would not leak. I only found it because I pulled the manifold and had to reassemble it.
My Ford uses a gasketless union between the manifold and the pipe, and it has to be sealed tight and perfect. Even a little bit loose and it won't seal right. Maybe yours is a touch loose?
Windows- they're what make a van worth owning! | | | Re: tick tick tick | Joined: Dec 2000 Posts: 3,750 Likes: 13 | OP Joined: Dec 2000 Posts: 3,750 Likes: 13 | finally had time to get more into this, found all the bolts on the passenger side manifold were loose! I snugged them up and the sound got quieter, so I'm on the right track. once the motor cools down enough (tomorrow) I'll pull the headers off, replace the gasket and put the bolts back in with some locktite 90 Astro - "The Grey Ghost" - Haulin Ass, Not kids.E-Z Vanners and West Vanners Council of Councils Board Member National Truck-in Board Support Team "No matter where you go, there you are." "If you can't do something smart, Do something right" "There are three kinds of people in the world, those who can count, and those who can't"
| | | Re: tick tick tick | Joined: Dec 2000 Posts: 3,750 Likes: 13 | OP Joined: Dec 2000 Posts: 3,750 Likes: 13 | Gasket replaced. Hardest part was getting the bolts lined up and started.
You could see on the old gasket where the leak was. I love a $10 fix 90 Astro - "The Grey Ghost" - Haulin Ass, Not kids.E-Z Vanners and West Vanners Council of Councils Board Member National Truck-in Board Support Team "No matter where you go, there you are." "If you can't do something smart, Do something right" "There are three kinds of people in the world, those who can count, and those who can't"
| | | Re: tick tick tick | Joined: Nov 2013 Posts: 3,692 Likes: 32 pooh-bah | pooh-bah Joined: Nov 2013 Posts: 3,692 Likes: 32 | Repairs that are inexpensive to make are always welcome. | | |
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