Liv2Ride

I have a '90 GT with 44k original miles. Since I have owned the car I noticed that when the car has been at running temp for 15+ minutes there is an obvious tapping type noise that appears to be coming from the left bank (driver side). You can hear like a slight valve tap but there appears to be a more solid type of tapping comes from deeper down - my guess a collapsed lifter. I know that our cars have roller lifters but are they hydraulic rollers? What is the possibility that one has collapsed or is sticking? I have had the car for about 2k miles or 6 months. The oil is semi synthetic 10w-40 and I changed it when I first got the car. I am thinking about changing it to full synthetic to see if that helps.

What is the chance the noise can just be a loose rocker bolt? I don't run the car hard and it does not appear to have had a rough life. I got the car and it was completely stock with the exception of the spark plugs and tires. I have gone through the entire car and everything that I replaced had to be done because of age and nothing else.

Thanks in advance.

luckythirteen13

you said you did an oil change when you first got it..6 months ago?

id do an oil change to start. with so few miles on the car i doubt a lifter has gone bad, but anything can happen.

Liv2Ride

I will get the oil change done in the next week. BTW my oil pressure is great. I get about 38lbs at idle when warm and up to 65lbs while driving at higher revs.

mdvaldosta

old oil or low oil can cause that. yes you have hydrolic rollers and your valvtrain is self adjusting - so the only way they could make noise is if one of em is collapsed or you have low oil, oil pressure, or old oil

Liv2Ride

mdvaldosta,

The level reads about 3/4 between low and high marks on the stick. The oil still appears honey colored and pressure is approximately 38 at idle when warm and goes as high as 65 when getting in the gas.

If I have a collapsed lifter what needs to be replaced? I would assume the lifters and push rods at a minimum. I would more than likely just replace the came too while I am in there. What is a good cam that will improve performance with the stock intake, heads and headers?

Thanks.

roundman

I would pull the driver's side valve cover and inspect the rockers and valve springs closely. look for any signs of looseness and cracking in the rockers and springs. pull all the rockers and inspect them closely for any signs of cracks and inspect the tips at the valve ends and also the pockets on the other end where the pushrods go. replace any rockers or push rods you may find with any large amount of wear on them. reinsitall the pushrods and rockers and make sure the push rods are fully seated in the pockets in the ends of the rockers. Torque all the rockers to specs and then with the valve cover still off, start the engine and check for any noises in the valve train. lay some rags or an old towel on the lower edge of the heads to catch any oil that might spill out. if this doesn't get rid of the noise, then I would get a dial indicator with a magnetic base and use it to check the lift on each rocker arm by turning the engine over by hand. a bad lifter will show up as the one with lift numbers that is much lower than the rest of them.

Liv2Ride

Is it possible that the header gasket can be starting to leak but I would not hear it until the engine got warm?

mdvaldosta

yes its possible, but you'd probably hear it louder if your engine was under load - and a valvetrain noise would be the same reguardless of load and only change with rpm or engine temp.

Justanother5.0

if you had an exhaust leak at the header.. it'd likely be more loud when the car is cold.. and fade away some as the car heats up.. if it was a big leak.. it'd be pretty constant.

Liv2Ride

I don't drive the car all that much - usually once a week to work and maybe run errands on the weekend. I am going to be driving it daily for the next month or so. I drove it to work today and I noticed that I only heard the slight tapping but not that deeper noise that I also mentioned.

As far as the noise being present any time other than idle, I noticed that when I hear it the noise seems to be most noticeable during idle and slightly off idle but it certainly does not get louder as the revs increase. As the revs increase it almost seems as if the noise goes away - not possible I know but it is hard to hear the noise if present when the rpm's go above approximately 1100.

In the next week I will change the oil to Mobile 1 full synthetic 10w-30 and see if it goes away. If after the change it is still there I will then replace the header gaskets.

What is the possibility that it can be where the pipe for the air pump connects to the back of the head?

Thanks.