Hi Forum,

I recently drove from the SF bay area to LA and back. At the start of the trip I overheated. The temp needle didn't go into the red but when I noticed it it was high in the white area.

I let it cool down on the side of the road and when I started it back up it made a pretty loud tapping or clicking sound.

I had promised my daughter I would get her to Disneyland so I decided to keep driving... My idea was to drive it to Bakersfield and evaluate things there. If I needed to at that point I would rent a car. As it turns out I just went for it...

We made it to Disneyland and a few days later made it home as well. The tapping is still there. This is what it sounds like on start up (cold or hot).


The sound does not really fade. It's constant.

Background:

1. There was always a pretty faint "clicking" sound before this.

2. The day before my trip I did a complete coolent flush and change - probably a bad move. It seems like I got a lot of sludge out of the system. I used Prestone coolent flush. I replaced it with cheap autozone antifreeze and distilled water.

3. After overheating and driving 7 or whatever hours I found that one of the bolts on the valve cover was completely loose. I tightened it up a bit and I think it made a slight difference in sound. There is oil around the cover gasket area but it doesn't seem substantial.

4. My oil level is staying steady. It is however a little over full - like 3/4" past the full mark.

5. I'm not used to pushing this car over big hills and I tried doing that with the AC on - stupid. That's when it initially over heated. On the way there and the way back home it seemed prone to overheating when pushed - even without the AC on. Driving through the Grapevines both to and from LA was an hair raising experience. I blasted my heater with the windows open to keep the needle in the middle of the temperature gauge... On the flats I could drive at 70mph with the AC on no problem - needle slightly below middle.

I've been reading as much as I can about this issue but I thought I would go ahead and post this. I will keep reading through posts and try to figure out a plan. I don't have the cash to spend at the shop - I spent it at Disneyland.

I'm thinking of trying an oil change and I'll probably need to change those valve cover gaskets since I drove hundreds of miles with the cover practically coming off. To find that 8mm-12 point - 1/4 drive was impossible!!! I found a 5/16" 12 point 3/8" drive during my trip and it seemed to tighten things up. Some of those valve cover bolts were really loose. I'm not sure if they are supposed to be that way?

Man, I really love my Discovery and I hope I can save her. I'm hoping for the best but will except the worst I guess.

Thanks so much for your help,
Ray

 

Your sound can be anything from a clogged rocker, a separated exhaust gasket, head gasket leak, stuck/burned valve, cracked head or a slipped liner. Hard to tell with a motor all buttoned up. I've experienced all of these on various vehicles I've worked on. To check for the obvious cylinder/hg leak/stuck valve issues perform a compression test. If all cylinders are within +/-10 psi of one another then remove the valve covers. 3/4" higher than the full mark doesn't bode well for your crank getting dipped either in which case you may have a bearing issue. The fact that you made it as far as you did says it's still in one piece.....it's salvageable.

If you squeak by on this one I suggest in the future to follow your gut and not drive it. Mickey Mouse has been around for awhile, your Disco will not be once you let into your wallet.

 

Does the immediate tapping sound on a cold start up rule out the slipped liner?

Thanks

 

Nope.

 

I removed my left side valve cover today. I had definitely heard something rattling around in there when put my ear to a large screwdriver.

besides being dirty I noticed that two of the pushrods are not able to rotate within their ball joint on their respective rockers. Is this normal? One rod from the front most cylinder will not move and one rode from the 2 cyclinder will not move like the others.

The rear most rocker (closest to the firewall) seems to have a lot of slop in it as it can slide about the rocker shaft a bit. Is this normal?

 

Video of under the cover...

 

Both actions are normal, first time inside a motor? What it looks like to me is your top end is oil starved, looks way too dry. No wonder your hearing ticking. Your top end should look like my attachment. That is a motor with over 160k on it and notice how wet it looks?

Do you have a copy of the Rave?

 

I changed a valve cover before but anything deeper than that is new to me. Thanks for bearing with me. I look into my oil pump and pressure situation when I can. My truck ain't going anywhere for a while... It may never drive again frankly.

So I just removed the shaft and rockers. I noticed that the two rods I was talking about are much higher seated than all of the others... Like the lifters will not sit flush - will not close?

I'm not sure what to do now. My rods looks straight. The rods that wouldn't "rotate" look like all the others.... Caked to hear with burnt oil...

I bought this car with 175K on it btw...

Thanks for your help. What do you suggest? I took pics of the "stuck" lifters but I'll need to make a darn website it looks like to past a url to the pics...

 

I have a copy of Discovery Workshop Manual which I've been using a bit.

 

Have no fear, I've got nothing but time......

The pushrods you cannot move are being compressed by the cam. They are pushing valves open. They're fine. The loose ones are at rest, not opening valves.......

As long as you have a torque wrench to reinstall the rocker shaft my next suggestion is to remove the shaft, keep the pushrods right where their bores are and do not drop them into the valley or you'll be removing the entire top end if you don't have a strong small magnet to fetch them back up.

What you'll be looking for is under each rocker there is a socket with a hole in the middle to lube the pushrods. Make sure you see a socket button in each lifter. Once you've checked each rocker then remove one at a time a pushrod. Check it's ball for roundness and then roll it on a flat surface to check for warp. I'm sure you'll find a few that look like mushrooms or at least starting to. Don't worry, just put them back in the same order you remove them.

Let's go back to the rockers. Check the sockets for oil occlusion at the oil ports. An overheat will thicken oil to the point where it clogs oil ports like now. Use a paperclip or thin wire to push into the port.

That's a start. Ticking isn't always catastrophic, believe me. You'll find out why soon enough and your truck will be on the road again soon.