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any way to determine if it's cavitation damage?

37K views 8 replies 3 participants last post by  twodog 
#1 ·
Hello to All,

Well, I bought my first diesel truck back in Feb '09, a '93 F250 with the 7.3L IDI turbo and 5sp. Love it.

Long story short; bought it with 137K on the clock, oil samples at 141K and 149K sent to Black-Stone labs looked good and showed no problems. A sample sent at 154K showed possible antifreeze contamination and levels of lead about average. The truck has 155K now.

The truck had a new radiator put in the day I bought it and I watched as the dealer put plain ole Prestone in it so I figured that's what it used. In the 18K miles I've put on it I admit I've only paid attention to the coolant level. I wasn't aware of the coolant system requirements, SCA's, and its susceptibility to cavitation until I discovered this forum and started researching.

The coolant level has slowly dropped and I've added plain ole Prestone when needed. I'm hoping the source of the loss isn't due to cavitation damage, but not knowing the maintenance history of the coolant system before I bought it I fear the worse.

The truck runs fine, like the day I bought it. I haven't noticed a lot of excessive smoke, antifreeze smell, or anything like that so I'm hoping I've gotten lucky. But like I said, fearing the worse.

Is there any way to positively identify whether or not the coolant loss is from cavitation damage? Any insight would be greatly appreciated.

Thanks in advance.

twodog
a.k.a. Lou
 
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#2 ·
If you have enought coolant loss through the cylinder walls to notice a drop in coolant levels then you might find it in your engine oil.

Check your oil cap for milk.
 
#3 ·
Ensure the rad cap is a new 13 lbs on the new rad. The line to/from overflow is working correctly ie clean and topped up. Ensure the line is sealed correcly at the rad to the little spout. The overflow res should be clean and the line will return fluid to the rad as the engine cools.

You can add the SCAs anytime now and with that low a mileage I think your OK.... most of us driving 7.3s did not know about SCAs until about 98 anyway. You could have a rad pressure test done.

Was the water pump replaced at anytime to your knowledge........
 
#4 ·
Plywood and cdnsarguy,

Thanks for the replies, they're greatly appreciated trust me.

I checked the oil cap and dipstick and nothing unusual there. Also checked the overflow tank and lines and all looked ok.

Not sure about the radiator cap but I'm headed out to get some of the SCA from NAPA and will go ahead and get a 13lb cap while I'm there. Also going to take it to a local garage to have them do a pressure check.

Not sure about the water pump ever being replaced, just know for sure the radiator was.

I did have the serpentine belt break once but only drove it long enough to move over 3-lanes onto the emergency lane. The oil sample from that run didn't show any problems though.

Thanks again and I'll post a follow-up to let you know how things turn out.

twodog
a.k.a. lou
 
#5 ·
Well, the pressure check was ok, just needed to replace the radiator cap. Three days of normal back and forth to work driving and I haven't noticed any loss.

Now just have to find out about the possible oil being contaminated with antifreeze issue that Blackstone mentioned. I'll keep a close eye out for any coolant loss (so far so good after 3-days) and get the oil analyzed a little earlier than normal just to be safe.

Thanks again for the help.

twodog
a.k.a lou

'93 F250 7.3L IDI turbo diesel
'64 Morris Mini-Cooper
 
#7 ·
For cavitation check.......

Cavitation Diagnosis
Source:
RPeter


--------------------------------------------------------------------------------
Updated November 7, 2001
As a 7.3L IDI & Powerstroke Ford technician I would like to clarify cavitation erosion diagnosis. I work on these engines all day every day and have developed my own test for this problem which has yet to fail me.

To accurately pinpoint the cylinder leaking the full steps are as follows:


Warm up the engine
Remove all glow plugs
Remove valve covers, rocker arms, and pushrods
Using an adapter that threads into the glow plug hole, attach compressed air (100-175psi)
Wait 3 mins for each cyl being tested.
A failed cylinder will make the Coolant level slowly rise and then overflow from top of radiator. It won't blow out of the radiator, but it will be obvious.
On Power Stroke Diesels a false failure may be indicated due to a leaky bottom injector o-ring. So, before you run off in a panic, consider that the o-ring may be defective, effect repair of the o-ring in that cylinder, then re-test.
NOTES:

Valve train should be removed to allow the piston, in the cylinder to be tested, to drop to BDC when shop air pressure is applied. This insures the valves will be closed and the entire cylinder surface can be tested under pressure.
You can purchase an air pressure adapter at most tool shops (they normally are sold to adapt a compression tester to the glow plug hole)
The cylinders that are most prone to cavitation are listed in order. #8, #7, and #4. Be sure to test all cylinders as I have seen some of the other cylinders occasionally deviate from this norm.
Most coolant leaks into the cylinder will show as the glow plug tip will be wet on the bad cylinder.
I have had very good success sleeving these engines in my business, but the key is finding a machine shop that has done this specific repair before. You don't want yours to be the machine shop's first kick at the cat!!.
 
#8 ·
I wonder if there is a point in the piston stroke where the entire cylinder wall would be exposed yet the valves would be closed so that you wouldn't have to remove all the pushrods and rockers?
 
#9 ·
Mucho thanks for the test procedure, very much appreciated. Right now it's pretty cold outside but that'll give me a chance to start putting the necessary adapters, etc together so when it warms up I can get started.

On the valve closing question, I wonder if they would both be closed when the piston is at the bottom of the power stroke? Even so, since I've never done this before I think I'd be better off following the procedure step-by-step and avoid the "never time to do it right but always time to do it over" adage.

I've exchanged a couple of emails with Blackstone labs and they recommended I have the oil analyzed a bit more frequently to monitor wear and change the oil at shorter intervals depending on the results.

Since the truck is my only means of transportation right now I'm still hoping I'll get off lucky. But, it is what it is.

Thanks again for the procedures, sounds like the information I've been hoping to find.

Take care and be safe out there.


twodog
a.k.a. lou

'93 F250 7.3L IDI turbo diesel
'64 Morris Mini-Cooper (currently undergoing some restoration work)
 
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