86 5.0 - ticking noise

[Mack]

As you may know I also have a 1986 GT convertible, with the 5.0HO engine, in a bit of a rough shape.

I've now noticed that the engine produces a clear ticking noise, after driving a while above 2k rpm - for example on the highway. When I slow down, I can hear the engine ticking quite loudly - also when I'm just rolling (not using throtle). After a while, the ticking disappears. Slow driving - no ticking. Stationary - no ticking.

Any idea what this can be? Should I be worried? The car is going to the shop soon anyway, but maybe I ask them to check certain things that may cause the ticking.

 

[RichV]

My guess would be a lifter. Could be a cam lobe/push rod/or rocker as well.

I would start by running the motor for a couple of minutes. Then removing the valve covers. You want the lifters to still be pumped up as much as possible. Then take your fingers and try to move each one of the pushrods up/down or side to side. If you have some that can be moved easily your problem is in those areas. Check pushrods compared to a good one for length and roll them on a flat surface to make sure it is straight.

Could be an exhaust leak as well, those can sometimes be heard as a tick.

 

[RichV]

Also, what oil do you use? I had a Mitsubishi once that did not like synthetic, all the lifters would tick about 1000 miles after an oil change.

 

[KillNThrill24]

I too would suggest a lifter. Follow Rich's steps and you'll find out if that's the case or not

 

[Ninety8stang]

I'm thinking probably an exhaust leak. Sometimes when the engine is under a load they can become more apparent. Can you tell if It's coming from a certain side?

 

[Mack]

Thanks all, I'm taking all this into account and have my shop check.

I'm thinking probably an exhaust leak. Sometimes when the engine is under a load they can become more apparent. Can you tell if It's coming from a certain side?

No, I only hear the ticking when driving, and the Flowmasters make quite a sound - combined with wind noise I can't tell where exactly it comes from. I would have to drive fast and immediately park it, maybe then I can find out.

I'm hoping for an exhaust leak

 

[uncltrvlnmatt]

If you have a bad lifter, normally they will tick constantly. An exhaust leak you will hear under a load and not at idle until it gets bad enough. If you have headers check your mounting bolts, and look for black soot around the mounting gaskets. Check the exhaust flanges where the pipes connect. You could also have a pipe rotting out. EGR tube. Do a good visual/physical inspection of the exhaust before ripping into the engine.

 

[CC'S95GT]

home made leak detector
http://www.sn95forums.com/showthread.php?57777-Exhaust-leak-Find-it-without-burning-your-hands

 

[GT Rob]

I have to run 93 in mine if I don't it well tick when I get on it

 

[Mack]

I have to run 93 in mine if I don't it well tick when I get on it

I think you are talking about gas? In the Netherlands, the worst you can get is 95...

Thanks for the comments everybody, I will check it out. Reading your comments I'm pretty convinced it's the exhaust manifold.

 

[GT Rob]

Yes sir