kgriffith

Hey, my 99 2500 has had an ongoing problem. My fuel economy has gotten worse and worse. Finaly I ran into the previous owner of my truck and he could hear the difference he said. He had removed the silencer ring from the truck and didnt hear it when I pulled up to his house. He removed the airbox hose from the front of the turbo and pointed out that their was oil all over the front of the houseing, infront of the fan. He then noticed that there were grind marks from where the fan had scraped the side of the houseing. He pulled on the fan and said there was too much slop and that he felt the turbo was done for(bad bearing). He drove it and said that the reason my mileage sucks(8-10mpg) is that there wasnt enough air going into the motor and its just pouring in fuel without burning it properly. What do you guys think? I looked around and was going to replace my turbo(hx35) with a PDR HX 35 which is supposed to be the same as the stock except it draws more air. Also I was going to put on a stage II predator so that I can improve the efficiency of my truck. Does that sound like the way to go? Will it solve my problem? Do you think the turbo was the casue of the gradual drop in economy? Anyone use the PDR HX35?

Big Smoky

If you don't plan on doing anything else to your truck then the PDR 35 will be ok. If you plan to go with a box or injectors, you might want to look into a PS 62 or HTT 62 or 64. My buddy just blew the seal out of his hx-35 and went with a HTT 62/14 on his '01.5 and loves it.

kgriffith

Do you guys think that the problem is really my turbo? I have gotten conflicting information. One person told me that if my turbo was done to the point where my gas mileage was at 8mpg that the truck would be ******* all over the place to the point where it would almost be undriveable. What else could cause a drop like that? The previous owner told me that he was getting 360 a tank at first and then getting 535 with a bully dog module. He removed the module when he sold the truck. I dont mind throwing a bit of money at this problem as long as it works. I dont want to replace my turbo just to replace my turbo.

Adam3291

If the turbo fan and shaft has alot of play in it its dead.

kgriffith

What is a lot of play? I would say 1/8 inch up and down as well as in and out.

Adam3291

Yeah sounds like it. Just re-read your orginial post. There is no question if the fins have been hitting the housing that the turbo is gone.

XLR8R

Holy Cow!!!

kgriffith

I will take a picture of what I am talking about and post it tommorow. Maybe you guys can tell from the picture if it is gone or not. Is there anything else that could cause my gas mileage to drop from 360 a tank to maybe 200 if im lucky? Since I got the truck, I replaced the sender assembly from the fuel tank because the return line was leaking from rust. I replaced the lift pump and also replaced the starter. The truck has 4.10 gears. 129000 miles. I cant figure out what else would cause this problem. Thanks guys.

TorqueJunkie

If the shaft is moving up a down then it is toast! There should be relatively no movement up and down and very little movement in and out, mabey .002-.004 or so.

gman07

I think thats backwards. There should be a little play up and down and very, very little in and out.

If either the turbine wheel or compressor wheel have hit their respective housing, the turbo's shot.

Mainemike100

Another vote for junk turbo. Like tourque said, the free play should be measured in thousandths, not eighths. If the fins are hitting the casting, then it needs to be replaced.

Rauschbo

....there is also the question of the turbo disintegrating if you keep driving it, exposing the engine to possibly catastrophic shards of metal scattered throughout it...

Adam3291

Yeah, he defanitly shouldn't drive it right now cause we have a member with a 12 valve that lost his turbo, kept driving it and now he is in the market for a new engine.

J BODY

...that sounds right to me. I've also noticed that the machining in the housing can often look like the impellar has been hitting it when it actually wasn't. Can you grab the shaft and physically move the blades far enough to cause it to hit?

...what kind of air filter do you run? If it's a K&N or that style of oil bath gauze that could be the source of an "oil film" on your impellar.

kgriffith

Well, I dunno if this helps but I installed a boost gauge on the truck this morning. I am making 18psi, so shouldnt that mean that the turbo is fine. I started the truck and had a friend rev it up while i watched the turbo fins. The moved fine and the spin looked fine too. And at shutoff it spun down fine and didnnt bind up. I think it migh have been just oil caked up that the fans spun through exposing the housing which made it look like it was scraping. If this is true then I am back to square one. I am getting about 8-10 mpg when I should have 16 or so. Should I get a controller for the truck and see if that helps? Also my transmission guy said that he heard a noise from the differential when he drove it(i didnt) He suggested rebuilding it, other people have told me that if it has a bad bearing you would easily hear it. He wants 700 to rebuild it.