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Overheating and a loud knock.
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Author:  jensational [ Sat Apr 17, 2010 6:46 pm ]
Post subject:  Overheating and a loud knock.
I've been having trouble with my 1969 Valiant overheating. I've changed the thermostat twice, back-flushed the engine, and finally took the thermostat out, but it is still overheating after a 30 - 45 minute drive. Now it's making a knocking sound that resembles the lifters knocking but is much louder. After I turn it off, it releases so much steam that, when we pull the valve up on the radiator cap, the overflow hose blows off. It has been mentioned that it is the head gasket blown, I'm afraid it's my rods. Any, more definite, suggestions?
Author:  carlherrnstein [ Sat Apr 17, 2010 7:18 pm ]
Post subject: 
Hate to ask obvious questions but, is your radiator pluged up? I've seen where dirty water was put in the cooling system :roll: idiots. Also hows your water pump? As for the nock, when it is idling put a screwdriver on the valvecover and put your ear to it and you will hear it, if it is the lifters.

good luck an welcome to the forum
Author:  jensational [ Sat Apr 17, 2010 7:26 pm ]
Post subject: 
I only put clean water into it, although it looks really dirty even after we back-flushed it. My dad replaced the water pump nine years ago, but it sat for three until 18 months ago. I know one of the rockers is tapping, but Daddy said, when he tried to set them, that one of them is going side to side, too. When he heard the sound yesterday he said it sounded like my timing, could this be the problem? The sound gets worse the faster I go, but not as bad when I coast.

Thanks for the welcome. I hope I don't become too much of a bother.
Author:  ceej [ Sat Apr 17, 2010 7:32 pm ]
Post subject: 
It sounds like you need to park that car until you find out what is wrong.

If it is a rod, you could be looking for a new motor rather suddenly.

CJ
Author:  carlherrnstein [ Sat Apr 17, 2010 7:56 pm ]
Post subject: 
Hows the oil pressure? I think if it were timing it would be more of a ping.
Author:  jensational [ Sat Apr 17, 2010 8:03 pm ]
Post subject: 
Ceej,
I'd love to be able to park her and am so scared it's the rod. How can I find another engine, let alone afford one? The first time I heard it that's what my gut told me. It's not often wrong.


I was thinking a timing issue sounded more like a clink than a knock. However, when we were back-flushing the radiator last week I heard (I was the only one, though. Out of my husband and dad.) a metallic-like clinking. Since they didn't hear it and my idler arm is loose, I thought it might have been that. But, could that have something to do with the knock?

I wish I had paid more attention to my dad growing up and retained it. Either that, or taken a mechanics course.
Author:  ceej [ Sat Apr 17, 2010 8:48 pm ]
Post subject: 
One of the best investments you can make is to get a Factory Service Manual specific to your car. A weak second would be Clymer or Haynes manual.
If the engine is overheating, that's bad news. As would be low oil pressure, or a bad rod bearing.
We're dealing with an older classic car here, but there are engines to be had out there. Hopefully it won't come to that, but one way or another, you need to identify the problem and address it.
If you need to depend on this car for transportation, you must take it out of service until you find out why it is exhibiting the behaviour you described.
Search this forum and the Frequently Asked Questions at the top of the Engine section here.
Do you have a thermostat installed? Many overheat issues occur when the thermostat is removed from the system. It regulates coolant flow through the engine.
Look up information here concerning the pressure relief valve for the oil pump. Contrary to the over-the-counter motor manuals, the pump can't be easily removed while the engine is in the car. Don't try to remove it, and don't mess with the cover plate unless you have a replacement o'ring ready to install.
The relief valve is on the bottom front of the pump installed on the engine. There is a cap that screws into the housing. A standard socket will not fit it. There is a washer that seals the cap to the oil pump. Under the plug is a spring and a "Plug" that regulates oil pressure. These can get stuck sometimes. Cleaning the plug and bore is fairly easy, and can improve oil pressure. Getting the cap loose and removing the plug is sometimes challenging. If you decide to do this work yourself, your going to need to make sure the cap is correctly tightened.
Your going to need to do some exploratory on the cooling system. If the radiator is plugged, it will need to be serviced, or replaced. At a certain point it is more cost effective to get a new or at least better one.

Don't start buying parts until you know what is wrong, and get some help if you aren't sure of something. We're always here, but there is no substitute for hands on. We simply can't tell what is going on through our computer screens.

CJ
Author:  Doc [ Mon Apr 19, 2010 8:41 am ]
Post subject: 
You need to figure-out if this engine has a bad bearing or not. If a bearing has failed, that becomes the #1 issue.
To check for bearing failure, remove and cut-open the oil filter.
If a con rod bearing has failed, you will find pieces of it in the oil filter.
(shinny flakes of bearing "babbit" material... it is soft material, like lead)

If the oil filter is clear, replace the oil filter and install a mechanical oil pressure gauge to find what the actual oil pressure is.
Report back with your findings and we can go from there.
DD
Author:  66aCUDA [ Tue Apr 20, 2010 12:13 pm ]
Post subject: 
How far are you from Silver Springs FL.? Charrlie S is there and a Great slant 6 Guru.
He is always willing to help.
Frank
Author:  jensational [ Fri May 07, 2010 10:14 am ]
Post subject: 
I just got my dad to listen to the knock and he said right off that it was a rod.
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