I have a strange engine problem that is stumping me. When the engine runs on normal street driving it sounds and runs fine, now when on the highway the engine develops a ticking sound from the drivers side. The wierd thing is that the tick will stay there for awhiel after I get off the freeway but then will go away if the truck sits for a while before starting again. I am assuming that it is a low oil pressure issue at highway speeds but I am wondering if any have seen this before?

I am now planning on an oil pressure gauge since mine only has dummy lights and also thinking about an engine flush. I know Disco Mike said that 6 quarts of ATF will do the trick, just wondering how long to leave idle with the ATF?

I really appreciate the help you all have given so far, I am new and the truck is a 94' that for the most part is great.

Thanks again!

 

I think 20 minutes is the flush time at idle.

If it was low oil pressure I'd think you'd hear it when idleing, not when on the highway.

 

You would think so. I took it to a mechanic and we checked over very well and could not get it to replicate while there. It just may have a mind of its own.

 

I would suspect leaking exhaust manifold gaskets. You say that the ticking never happens if you drive around town - no matter how long you drive it? How soon after getting on the freeway does it start? If you continue driving it on city streets after getting off the freeway (without shutting it off) does the noise eventually stop? How many miles are on the engine, and has it had major work on it? Head gaskets replaced?

By all means do hook up an oil pressure gauge, but I really don't think it is oil pressure related. Oil pressure increases with RPMs so you would see the problem more if you let the truck idle for a few minutes.
Piotr

 

Engine has 135K. When I get on the freeway it starts fairly quickly and the engine runs a little rough. After I get off the freeway it will still make the noise but if driven around for about 20min at maderate speed it goes away again. I can cruise around at about 65mph and no noise but when over it will start. It is very confusing and I am not sure what would cause it.

I have no clue when the head gaskets were changed last or even the exhaust manifold gasket. I would have assumed that if it was exhaust related it would be louder when cold and quiet when it got hot and expanded to close the gap. There is no foam or anything in the oil so I didnt think there would be a problem with the Head gasket.

If any of that helped out more for an expalnation then great, I need all the help I can get.

 

I recently started having a similar problem - on idle no noise and the moment I press the gas and rev up the ticking sound starts...let go of the gas and it stops.

From what I have read I understand it could be either worn cam lobes or the engine needs flushing (which I think I'd eliminate in my case as I change the oil every 5,000kms). Any other possible causes for this ticking sound?

Engine is a V8 3.9 with 268,000kms on it (don't think anything major has been done on it).

 

At your mileage, you could have a couple of bad lifters, back rocker arms or a flat cam lobe. It is always worth the money to do a reall good engine flush just to clean up the engine and bring back some oil pressure lost to sludge build up.
Mike