PTU Failure types
- Thread starter lamrith
- Start date
802SHO said:
IMO the faliures of the PTU are a combo of heat and fluid failure. The cats get hot and literally bake the PTU. In turn that cooks the fluid and literally changes the fluid into a thick grease like substance. The thicker substance cannot cool and lubricate the direct drive gears and failure is imminent.
On the liquid cooled units (PP and PI vehicles) I have seen a reduction in PTU failures. On my personal PP SHO, I researched all the records from the one Ford dealership that worked on the car. Previous owner purchased my SHO new at said dealership. Same dealership did all of the maintenance and recall work, and then after 5 years took the SHO back in on trade. In the records the PTU fluid was not changed.
I changed the fluid myself expecting the worst at roughly 55k miles. I was presently surprised with the fluid that came out. It was nothing like other people had claimed to pull from their PTU's. It was still really viscous and not completely black. When strained the metal shavings were minimal in the oil and on the drain plug. Having a liquid cooled PTU is the best thing to have with this set up.
I wish I still had the pictures. I changed my 13pp fluid at roughly 58k it was near a solid. It had the consistency of wheel bearing grease almost. I did 2 more changes before 70k and it got much better. There was never a ton of metal. I may have just caught it in time. I agree the heat of the downpipes baking the fluid.
griggs95
New member
I'm not sure I've been lucky or what. I have 98k on my 11 PP now and I went through my records and realized my PTU fluid was drilled and tapped at 40k. Also, that was the first PTU fluid exchange the car ever had. I'm shocked how fast time has gone and just totally overlooked this critical mistake of mine.
I had taken it to a place that had never done anything like this and was excited to do the work since they had seen PTU failures before. I ran the car at a road course type of event in 90 degree temps just after doing the change and no issues other than heat soak (of course).
In panic, I just finished the fluid change a couple weeks ago and found the fluid still drained (thanks to the tap) but around 8-9 ounces came out. I thought 'my god, I'm one lucky mofo'! Nothing would lead me to believe the fluid was low, or that old while driving it this long.
The fill plug was absolutely coated with sludge, the fluid was dark black and stunk BUT it flowed out the drain plug slowly but surely. Also, the car was cold from sitting over-night on jack stands.
One last really important thing. The shop that did it did not put enough fluid in it when they did the tap and fill. I remember them saying that Ford recommended to put enough in and check it with a bent zip tie (no joke) and put it in the fill hole to check fluid levels. I laughed but my main concern at the time was that its done and I put the best stuff I could find in there, so I was ok with it.
I'm thinking the only reason my PTU is still alive it the quality of the fluid I used. And maybe, just maybe its because I drive in the summer without the big plastic shielding (forgot the technical term) underneath the car. My theory is it might help cool the PTU and down pipes with more turbulent airflow.
Now take a guess which brand of fluid I put back in?
I had taken it to a place that had never done anything like this and was excited to do the work since they had seen PTU failures before. I ran the car at a road course type of event in 90 degree temps just after doing the change and no issues other than heat soak (of course).
In panic, I just finished the fluid change a couple weeks ago and found the fluid still drained (thanks to the tap) but around 8-9 ounces came out. I thought 'my god, I'm one lucky mofo'! Nothing would lead me to believe the fluid was low, or that old while driving it this long.
The fill plug was absolutely coated with sludge, the fluid was dark black and stunk BUT it flowed out the drain plug slowly but surely. Also, the car was cold from sitting over-night on jack stands.
One last really important thing. The shop that did it did not put enough fluid in it when they did the tap and fill. I remember them saying that Ford recommended to put enough in and check it with a bent zip tie (no joke) and put it in the fill hole to check fluid levels. I laughed but my main concern at the time was that its done and I put the best stuff I could find in there, so I was ok with it.
I'm thinking the only reason my PTU is still alive it the quality of the fluid I used. And maybe, just maybe its because I drive in the summer without the big plastic shielding (forgot the technical term) underneath the car. My theory is it might help cool the PTU and down pipes with more turbulent airflow.
Now take a guess which brand of fluid I put back in?
shoNoff said:
But did it fail? I kid, I kid. This is very interesting to say the least. I am not saying the PP PTU don't fail, I am saying they have a better track record of not failing possibly because of being cooled.
I am working on my DP's this week. The guy that does my fab work became unavailable. So I am going to wrap them up and install them this weekend. I want to safe guard the PTU at all costs.
I'm on the same page with the cooler, the PP capacity is also 17 oz if I recall correctly. Not sure what the non PP capacity is. I pulled about 12 oz from mine through the drain plug, car tilted. Hopefully the other 5 oz was trapped in the cooler. It would be interesting to run it hard and drop the shield off and shoot the cats and ptu with a temp gauge. I'd also be curious if the cat's on the tuned cars run hotter.
SM105K said:
I agree the cooler absolutely helps. I bet if mine didn’t have a cooler it would have failed. The only thing I don’t really know is how the previous owner treated the car. I can take a wild guess he wasn’t up on maintenance. I’ve had one lubrication failure after the next.
) leave the PTU.My experience with CO2 comes from 10 years of playing for a promotional paintball team in the 90's/2000's. The problem is when you dump a lot of CO2 quickly it changes states from a liquid in the tank to a solid (dry ice). With the markers it lead to extreme pressure drops, loss of velocity which is why high pressure nitrogen systems came into play. I don't know if you could have a tank that was big enough to spray any length of time without causing this.802SHO said:
I just quickly read something else entirely about using No2 or Co2 to cool the intercooler. Saying residual gases can get into the intake and Co2 leading to power loss that way or No2 causing an untuned for increase in power.....seems like there's always a snag with these type of things.
Well I think the most cost effective direction to go would be to attack the downpipes with a thermal coating....and then top it off with an exhaust wrap....now I bet that would dramatically reduce the heat and naturally not transfer to the PTU. Better than nothing
https://www.summitracing.com/parts/zyc-10004?seid=srese1&gclid=CjwKCAjw1f_pBRAEEiwApp0JKJ2hjk7HUe22BqSxfR1agAscarSiw6LUA5Pc0z0TKIKbY1vRBphgbhoCRKUQAvD_BwE
Well I think the most cost effective direction to go would be to attack the downpipes with a thermal coating....and then top it off with an exhaust wrap....now I bet that would dramatically reduce the heat and naturally not transfer to the PTU. Better than nothing
https://www.summitracing.com/parts/zyc-10004?seid=srese1&gclid=CjwKCAjw1f_pBRAEEiwApp0JKJ2hjk7HUe22BqSxfR1agAscarSiw6LUA5Pc0z0TKIKbY1vRBphgbhoCRKUQAvD_BwE
802SHO said:
If you want to cool the charge air, you need to use a small shot of nitrous with a dry shot fogger. If you have the fuel capabilities that will be your best bet. It tanks the intake temp which increases air density, which in turns gives the ability to burn more fuel because of the chemical reaction and increased oxygen levels, and the result more POWA. I would run it directly post turbo. There are numerous disagreements about this regarding pre and post turbo, but I have had success directly POST turbo.
When I first put my blower on my 5.0 Fox Body Mustang, it did not have intercooler. To cool the charge air, we tapped a fogger post SC head with a .026 jet (very small) and the car picked up 58 rear wheel hp.
You also have a lot of experience with nitrous too. Your knowledge is much appreciated and I think Nitrous gets a bad rap bc ppl don't do their homework and misuse it...then turn around and talk a bunch of crap about it. Like with methonal. It works extremely well and is relatively safe if it's set up properly and used accordingly.
802SHO said:
Nitrous is safe if used properly. I have had it on numerous applications and have never melted down a motor. Worst was a melted ground strap and a blown head gasket, both my fault. I had a 186 hp to the wheel motor, live for years on two kits both pilled at over 150 hp and 175 hp. It was safe.
Before the naysayers come out of the wood work...
We are not using it as a direct power adder. We are using it as a chemical intercooler/atmosphere conditioner. Yes more fuel will need to be added, but for the cooling effects the fuel adage will be minimal. If the car has a proper fuel system in place, there is little to worry about, and the performance gains esp on a FI set up are astounding.
