I just rebuilt my '89 4.9 six, which was running fine until I left the radiator cap off and scored the pistons. It's running well, but I have a missing hose, apparently. The front outboard nipple of the vacuum tree has nothing on it and I can't find any hose end to go there. The engine was running fine before and the leak at this fitting really messes it up, so I know something was there. Can someone please tell me what? I've searched the forum and the internet, but can't find anything on the tree connections.

Please help, thanks,
Wilson

 

Try help or dormann, they have alot of oddball fittings.

 

The fitting is OK. I need to know what is supposed to be connected there.
Thanks,
Wilson

 

Silly me! It was the brake booster connection. I was looking for something small...bad case of cerebral-rectal inversion!
Wilson

 

more importantly...

how does leaving the radiator cap off score the pistons...? did you over heat the engine...?

Just wondering because the very 1st thing I do to any of my vehicles is rip the guts out of the radiator cap so it is a pressure-less system...less pressure = more flow...more= better cooling...

 

The pressure is caused by the heating and expansion of fluid rather than restrictions in flow capacity. This is important because the water pumps are not a positive flow pump, meaning that they will not build pressure.

 

pumps do pressurize with the flow....with volume come pressure...you can have 5psi just off the pump alone...

I agree that the heating and expanding of the fluid creates some of the pressure but not all of it..but that still doesnt answer the question...I know the answer..I just want to see if the OP does and why...

I run open systems on almost all of my engines...

 

WEll, the linkage between the radiator cap and pistons is very subtle! It's like this: Wife loses tranny in Voyager van 200 miles from home. "No prob", say I, "I'll just hitch up the flatbed to the F-150 and run up there and bring 'er home.". On the freeway in no time, enjoying the really smooth engine with the new plugs, listening to music, watching the trailer in the mirror, thinking about the $1800 the tranny repair will cost, going 75, at least, and thinking about how great it is to have a truck and plenty of money for gasoline. Beautiful day, all's well, you get the picture.

But why is that semi beside me making all that clattering noise? Speed up a bit to get by him. OOPS, noise now louder, better pull over! Coast to nice grassy area beside the hwy, engine frozen solid! Looked under hood...no smoke, no steam, not a great amount of heat...guess that 75 mi/hr wind cools things a bit.

Nice radiator cap still lying on the plastic beside the radiator, just where I left it last night after topping up the coolant for the big trip.

And you still want to run an open system? There is no real pressure buildup on the output of your water pump. If there were, the water would come right out the open cap until the pump couldn't pick up any more. The pressure in a properly operating cooling system is vapor pressure of the coolant. If there is expansion, coolant will go into the reservoir. In fact, the pump may work slightly better with pressure, because the coolant is slightly denser. Furthermore, with the cap on you can build up some extra pressure to overcome a partially clogged system. My Toyota and Escort go YEARS without losing significant coolant, whereas the '53 Chevy mentioned above would boil some out unless there were a pressure cap installed. Lots of new cars run over 200 degrees and couldn't run across town without the cap.

Unfortunately a coolant pressure switch wouldn't help, unless you blow a line. An overheated engine will have high steam pressure, unless you blow a hose or radiator tube. Perhaps an electrical interlock for the cap, not a hard thing to do at all, is a good idea?

Now she's all rebuilt and I decided to put on new calipers, PS pump, and idler pulley while I was at it. She's still in the garage on blocks, but the idle is pretty smooth and getting better. The rings are still quite tight, so I expect further improvement. BTW, cranking the engine with the spark disconnected (coil shorted, BTW) primes the oil pump in about ten seconds. The oil pressure comes up to the operating level just on the starter!

That's about it...really dumb thing to do, but I've been driving 53 years and this is the first one I've fried, and hopefully the last!

If anyone asks, getting the crossmember out of a truck that has been in salt a good bit is a bitch, the worst part of the job! The bolts are hard to get to and lead to a lot of cussing and banging around. The Mazda tranny with integral bellhousing is BIG and fairly heavy. The Harbor Freight tranny jack, which I hope to never need again, was a real help.

Oh yes, what about the Voyager? Wife rented a car and finished the trip.
Chrysler dealership diagnosed the tranny and let the van stay on their lot.
Son came with his big Ford van and we hooked the trailer to it, loaded the 150 thereon and brought it home, only 30 miles. Then I took the van and trailer to the mountains, loaded the Voyager, and had a nice trip home. Only burned about $75 worth of gas. Tow quotes were $500-$600, so I did OK, except for $800 (machine work and parts), about $200 worth of fluids and small parts, $100 for books, and several days of work! Still better than $1500 for a long block and $1500 for installation, if I hadn't done it myself. ALSO, it was a great excuse to buy a couple hundred bcks worth of new Harbor Freight tools, so I have almost all of them now!

Enjoy my pain and double check your radiator and oil caps before starting out! Anyone want to buy a tranny jack?

Wilson

 

are you right in the head??

 

I certainly think so. I got all those wires and hoses back and I seem to have tightened all the bolts OK.

How about you?
Why do you ask?

Wilson