Engine knocking
 

Well I think it happened to me today,, i replaced my alternator after letting the truck sit for a few days,,, when trying to start it again,, heard a hard knock,, then when it started a huge cloud of vapor issued from the exaust smelling heavily of coolant. I then heard the knocking in the engine. I have no idea WHAT is knocking, I just know that it is bad. I am no mechanic, so if yall could inform me,, what gasket causes the influx of coolant into the cylinders, and what usually happens to the engine to cause the knock? I have a stock engine with 144,000+ miles on it, owned for 2 years+ and the alternator is the first component i have had to replace,, I LOVE MY TRUCK,,, AND DONT WANT IT TO DIE.

It's your lower intake gaskets, it's your rod that is knocking(bent or broken), and I hate to be the bearer of bad news , but you need a new engine. Your cylinder was full of coolant due to the gaskets leaking while it sat. Liquid cannot be compressed, therefore the rod gives, and you end up rebuilding or replacing the engine. I am truly sorry, as I barely dodged that bullet last year, and so did Brian. BTW, what year is your truck?

hi macdug, did your engine continue to knock after it had been started or did it stop after all the coolant had been evacuated from the cylinder.
if you think the knock stopped, you may be lucky and get away with the cost of new lower intake gaskets.

What do you mean by "lower" intake gasket,,, is that for cylinders 1-3,, and the upper for cylinders 4-6,, and for "rod" u mean the connecting rod between the piston and crankshaft,, I'm not a mechanic but know some of the parts, i'm just clarifying. New engine eh,, can't just replace parts? It's a 1998 shortbed, flareside, red, plain jane pickup,,, but its the best pickup i have ever had,, If i have to replace,, go for a 2000 4.2 or newer?

Hi bokker, knocking continued,, and i drove it home from the base. A friend of mine thinks it could be a pushrod, i told him no,, that it sounded deeper in the engine. So I think that it is probably a connecting rod,, usually how much does that cost to replace?

travlnman was dead right with his prognosis, sorry cannot help about cost due to living in uk. all i know is i payed over the odds due to export tax.

Your intake is split horizontally into two pieces. An upper aluminum,or plastic intake,(depends on year), and an aluminum lower where it actually attaches to the heads. The lower intake gaskets leak where they meet the head,if it's near an intake port, it leaks in the intake port, and if the valve is open, it goes straight into the cylinder.At a bare minimum you are looking at replacing one rod and piston assembly, but with that many miles (my '02 has 193,000) I would do it all or just buy a crate motor. Prices can be all over the place, but information is your weapon. Surf til your eyes hurt,, then surf some more to find the best deal. Maybe someone here will post with some price info. Again, I am truly sorry!

Ive looked online at reman engines,,, prices vary from $1149 to over $2600. I took the truck to a shop today and he says the the noise is definately coming from the bottom end, (connecting rod or bearing, possibly a main) he will drain oil and check for metal or pieces and will call me tomorrow. I guess a full bottom end rebuild (crank, pistons, rods etc.) will be my best bet. I just hope my block is unharmed. The shop owner is ex-military as am I, and I think he will be fair with me. Thanks for your help guys!!

FWIW - I was at my local Ford dealer today (some warranty brake work on my "05). They had a Ford re-man 4.2 crate motor sitting there for sale. It would require transfer of intake, throttle body, etc. from your engine.

$2,400

I talked to the mechanic today,, he now thinks the noise is coming from the timing chain cover area. He also said the the noise dosent sound like a bent/broken rod but will let me know what he finds out. I instructed him to replace the lower intake gaskets anyway,, so I'm hoping it's not as bad as I first thought. I'll keep you all posted.

Doug

Hey macdug, what's the prognosis? How did you come out?

Indeed! We want an update!

Thanks for thinking of me,,, sorry i havent gotten back. The mechanic says there is scoring on 2 rods, and on the crank (bearings) and possibly thinks that the main bearings are going as will,,, Just guessing ,, but scoring on the rods also means that they have been hitting the cylinder walls,,, is that right? He tells me that it is more economical to buy a new engine. Went with A Two Z Engines, will call them tomorrow to place the order. Engine cost: $1799 core- $400, free shipping to shop and for core back to A Two Z. So total cost of engine 1799. Warrenty is 3 years or 100,000 miles. How does that compare to what you guys have seen. On a side note,, got another job to help pay,,, working at Black Hills Ammunition. Have to ride Harley to work. At least weather is pleasant right now!
Doug