I'm starting to get pretty frustrated with this truck. Lately it has been running hot so I have been trying my best to flush/clean the cooling system. Today I was running some Prestone cleaner through the system and while watching the engine idle I noticed the belt tenioner was wobbling a good bit. The truck ('94 4.9 auto) has a new S-belt because the old one blew out on me while driving. I got the most expensive one I could find and it is installed correctly. The tensioner never did this before and now the battery voltage gauge on the dash is reading higher than it used to. WTF is happening? Also, when idling now the truck has white, sweet smelling exhaust. Never did that until I put in the radiator cleaner. On top of my persistent code 624 and misfire (despite having a completely new ignition system, fuel pump and clean sensors) this is getting to be a money-pit, time consuming, frustrating vehicle. It's like I don't have enough money or time to address everything at once and I just spend all my extra time reading the Haynes. Where do I go from here?

 

Remove the serpentine belt from the tensioner pulley and check the play of the pulley by hand. See how much it moves by tilting it back and forth and spinning it by hand. If possible, get a measurement of how much play it has.

As for the exhaust, there's a few possibilities, such as a leaking intake or head gasket, but none of which I am certain of how to diagnose.

Code 624 indicates circuit failure, not necessarily component failure. I'd start checking continuity between all of your transmission wiring and the computer, and clean all the related connections you can find.

 

Thanks for the level headed response. I was so frustrated with the truck last night when I posted. Your signature perfectly describes how I'm starting to feel haha.

 

how is your water pump maybe it is seizing up and thats why its getting hot and the belt is wobbling. Just an idea

 

How can I test it? It looks OK and is turning just fine with the engine running.

 

Im not real sure

 

Coolant in the exhaust is never a good sign.

What does your oil look like?
What does your coolant look like?
What are the compression measurements on all your cylinders?

That misfire could be due to coolant in the combustion chamber due to a blown head gasket, cracked cylinder head or cracked block.

I hate to be the bearer of bad news, but you more than likely have a pretty sick truck.

Jason

 

Oil looks great and so does the coolant. Before I dumped in the Prestone cleaner stuff the truck never did this. Haven't tested compression.

 

That "cleaner" stuff does nothing but harm gaskets and the cooling system.. Bad idea.

Valvoline instant oil changes do a full system coolant exhange with fresh coolant pushed and pulled through the entire system..

For only 89 bucks plus tax..

 

Belt off and feel for play on the axel.
Should spin very easily by hand, and the axel/belt-wheel shouldn't move side to side or feel loose.
I'm not sure on the 4.9 but on my 351 the belt's also an **** to line up properly, and if it's just a wee bit of it'll wobble and tend to get worse over time, check for this as well.

And as they said, seems like you have a gasket out, you loosing coolant? Any puddles?

 

I will check on that thanks. No puddles but I dunno if I'm losing coolant any other way. I'm starting to fear the gasket is blown somewhere but it doesn't really have any other symptoms, just the sweet smelling-exhaust and mysterious misfire. I'm going to refill with fresh coolant this afternoon and see if it is still burning it. I've torn down a good bit of the engine before to replace the valve cover gasket and some other things. Is the head gasket just a few more steps from that? Take out the rods and pull the head?

 

Pretty much, usually you need to take the headbolts of a little bit at a time in a spiral pattern (wich may start and end on different positions depending on engine) so that the tension doesn't crack the head. Your haynes will have information on this, otherwise google is your friend.
Same goes for putting it back in, and most modern engines at least have headbolts wich are designed to strech when you tighten them, so ideally you'll need new ones putting it back together. Not sure about this particular engine, how sensitive it is, but it's a general rule of thumb to put new ones in.
Same goes for the gasket itself, wether it's broke now or not, it will be when you've had the head of.

But try filling it up and see if it drinks coolant first. No reaon to tear the engine apart for no reason, check properly underneath so it really isn't just leaking somewhere either....

Good luck!

Edit: For gods sake keep track of wich pushrod goes where aswell!

 

Here's my thread of videos I posted of year of tear down to head gaskets.. The videos were of a 351W.. Same concept as a 300..

Rebuild is opposite of tear down with the exception of going in order of a torque pattern and torque specs..

Also those head bolts on your engine are torque to yield.

You'll need new head bolts when you do head gaskets..

http://www.ford-trucks.com/forums/11...l#post10894549

 

Very cool thanks!

 

I would run it at temp, and pull each plug wire one at a time. If the exhaust smell changes...read that plug compared to the others...