99 Ford 7.3L 500K miles, Engine Shuttering and Axle Noise
#1
10-21-2008, 10:46 PM
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99 Ford 7.3L 500K miles, Engine Shuttering and Axle Noise
I am new to this Forum but have joined to see if anyone may be able to help me diagnose my current sticky situation. I have a 99 7.3L f-350 that has 500,000 miles on the original engine, no aftermarket modifications whatsoever (accept for some nice new heavy duty glow plugs 
). Around 480K the motor was showing a serious drop in power all around, rough starting, very sluggish, heavy shuttering before and slightly after reaching the first line on the temp gauge. So on an endeavor to find a solution to keep her running smooth, I replaced the glow plugs as suggested by mechanics and books. After I did that, the motor runs like new with all the power it once had but still I encounter the shuttering at low rpm's (not nearly as bad) aswell as much better starting, but still takes much to long to warm up to that infamous line on the temp gauge. The second the arm on the gauge hits the line, the motor runs absolutely perfect... before it, it barely rolls down the street... the time it takes for it to stop shuttering is now taking a bit longer and I'm worried it may be time to do some serious work to reverse the growing issue :'( Any suggestions or ideas even as extreme as complete rebuild are more than welcome! and as a side note, for anyone with this same truck or similar, whenever I make a right turn, something on the driver side near the axle is making a very disturbing crunching noise that you can feel through the floorboards.... no wear or contact marks anywhere and the 4x4 is completely unengaged. >.<
Also, after stopping from a long freeway drive, the idle is unsteady for about 5 minutes....
Any help is very appreciated
). Around 480K the motor was showing a serious drop in power all around, rough starting, very sluggish, heavy shuttering before and slightly after reaching the first line on the temp gauge. So on an endeavor to find a solution to keep her running smooth, I replaced the glow plugs as suggested by mechanics and books. After I did that, the motor runs like new with all the power it once had but still I encounter the shuttering at low rpm's (not nearly as bad) aswell as much better starting, but still takes much to long to warm up to that infamous line on the temp gauge. The second the arm on the gauge hits the line, the motor runs absolutely perfect... before it, it barely rolls down the street... the time it takes for it to stop shuttering is now taking a bit longer and I'm worried it may be time to do some serious work to reverse the growing issue :'( Any suggestions or ideas even as extreme as complete rebuild are more than welcome! and as a side note, for anyone with this same truck or similar, whenever I make a right turn, something on the driver side near the axle is making a very disturbing crunching noise that you can feel through the floorboards.... no wear or contact marks anywhere and the 4x4 is completely unengaged. >.<Also, after stopping from a long freeway drive, the idle is unsteady for about 5 minutes....
Any help is very appreciated
#2
10-22-2008, 07:58 AM
Diesel Enthusiast
4x4 sound could very possibly be the sway bar links, they may not look worn, but the bolts that go through to the frame will be loose in the hole
#3
10-22-2008, 08:46 AM
Im wondering about compression and maybe when it is cold the pistons are not expanded enough and that is why it has a loss of power til it warms up and the piston and rings get a good seat...that is just a guess but with 500,000 on the clock it might be getting close to time for an overhaul.
Other than that check the the sway bar for the wear and also you might want to change your rear diff oil it could be broke down pretty good if it hasnt been changed(which they rarely do) and add some limited slip additive when you fill it back up it could be your diff clattering
Im not sure how you would do a compression test on that engine, i know diesels are a little more involved then a gasser to do compression tests so, check back later today and hopefully someone with a little more 7.3 experience can help ya out
Check the headgaskets too
Other than that check the the sway bar for the wear and also you might want to change your rear diff oil it could be broke down pretty good if it hasnt been changed(which they rarely do) and add some limited slip additive when you fill it back up it could be your diff clattering
Im not sure how you would do a compression test on that engine, i know diesels are a little more involved then a gasser to do compression tests so, check back later today and hopefully someone with a little more 7.3 experience can help ya out
Check the headgaskets too
Last edited by stkdram55; 10-22-2008 at 08:50 AM.
#4
10-22-2008, 04:41 PM
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Ok yeah thanks I'll look at my sway bar links to see if there is any clues to the clattering and look into some compression testing ideas too.
#5
10-22-2008, 06:15 PM
Diesel Enthusiast
i believe they make an adapter to check compression by taking out the glow plugs one by one and checking it like a cars sparkplug.
#7
11-24-2008, 09:23 PM
I have seen a tool you put in place of the glowplugs to test compression, just cant remember where
But the high oil pressure regulator is what I would look at, that is the number one problem with international and CAT engine rough idles,
if you have a scanner watch the high oil pressure at an idle, if it jumps around like 420psi to 580psi the regulator is bad and is causing the rough idle, I just changed mine and I wish I had done it 2 years, it purrs like a kitten at an idle now, and raised my WO oil pressure and really brought the engine back to life
crunching noise I have in my 99 F450, its the bottom ball joint on mine, jack it up and look for play top to bottom, in and out, also I have seen an unused front axle u-joint rust up and get tight and make noise even with the axle not locked in, its always good to lock the hubs in once a month and warm up the grease and spread it out, I have pulled so many old front ends apart that never got used in 4wd and the top of the parts are rust because all the oil and grease had settled to the bottom and exsposed the top metal to air moisture.
But the high oil pressure regulator is what I would look at, that is the number one problem with international and CAT engine rough idles,
if you have a scanner watch the high oil pressure at an idle, if it jumps around like 420psi to 580psi the regulator is bad and is causing the rough idle, I just changed mine and I wish I had done it 2 years, it purrs like a kitten at an idle now, and raised my WO oil pressure and really brought the engine back to life
crunching noise I have in my 99 F450, its the bottom ball joint on mine, jack it up and look for play top to bottom, in and out, also I have seen an unused front axle u-joint rust up and get tight and make noise even with the axle not locked in, its always good to lock the hubs in once a month and warm up the grease and spread it out, I have pulled so many old front ends apart that never got used in 4wd and the top of the parts are rust because all the oil and grease had settled to the bottom and exsposed the top metal to air moisture.
