Can someone give me some information on the PrePower Sroke Diesel engines concerning quality, service, power & longevity. I'm looking at a 1988 model with 125,000 miles. I'm looking for some advice as to what to look for. Thanks in advance for your help.

 

WELCOME to the site, please read the Guidelines… Check out the list of forums and make sure you read the headings and Read First: notices in each forum. The members in this forum are very knowledgeable about these trucks, they will be by..... and help you with your question.
Good luck with search.
Enjoy FTE

 

444 cubic inches
22.5 to 1 compression
185 horsepower
320 ft lbs torque

Much more dependable than a Power Stroke, not as powerful though.
With proper care it will easily last over 300,000 miles.
Very simple engine, needs fuel and air to run.
No computer to hassle with.

The worst thing about them is cavitation. This is an erosion of the cylinder liners that can cause engine failure. There is an addative for the coolant called DCA 4 that prevents this problem. You must install it with new antifreeze, and it must be maintained at a proper level of concentration which is checked with test strips.
Both of these are available at NAPA.

I recommend changing the filter and oil at 3000 miles, use a good diesel rated oil, 15W40 unless you are way up north where it is real cold.
Fuel filter should be changed about every third oil change.
Air filter should be changed about every other oil change unless you are in real dusty conditions, if so change it every oil change.
Buying fuel at a station that has lots of truck traffic will lessen the chance of water in your fuel. I found a good truckstop near my house, I have never had water in the fuel in 18 years. All but about 5 tankfulls of fuel burnt in my truck came from the same station.
If you are where it gets real cold, you should run an anti gell addative in the fuel when it is below 15 degrees, or going to be below 15 degrees while you are driving.
Good batteries and charging system are important for it to start good. Watch the connections, water levels and battery condition closely, it will save you from being stranded. Extended cranking of the starter is bad for the starter. 20 seconds of cranking, then it is time for a cool down period of a minute or so.
The glow plug system is the only other thing that you must maintain. If it is working correctly the engine should start in five seconds or less. There are lots of threads here about that.

Last words of advice, do not run it out of fuel. They are hard to restart if you do.

If you have more or specific questions, someone here will be along to give you help.
I would not trade my diesel for 5 gas trucks just like it.

 

The IDI has around 345-350ftlbs of torque which is alright they do have enough low end grunt off the line to get the load rolling. I have pulled along a flat road in OD at 1000rpm wasn't going very fast mind you.

The worst thing about the IDIs is cavitation like Dave said which has killed many IDI engines. Ford never did meantion or know to put a coolant additive in the cooling system to combat the cavitation problem. All diesel engines have cavitation the old 7.3 IDIs had the problem more because the cylinder walls are thinner along with the compression is 21:1 so there is alot of stress on the cylinders.

I wouldn't be worried about buying a IDI but you do have to know the cooling history if you don't that you are taking a risk. These IDIs die from cavitation without warning and its expensive to replace the engine.