Hi! I'm Doggo, long time lurker, first time poster. The Fiero has long been my dream car and about a few months ago I finally got my hands on an automatic 85 duke! 122k miles, she runs pretty good, previous owner did a lot of work on her. I've fixed a few things that have come up myself (with plenty of help from you guys lol) but now I've got a problem that I think may do my poor duke in. I'm not super mechanically inclined, so please bear with me. I think my piston rings may be going. The dash oil gauge reads lower than I'd like it to (15-20) but only once she's warmed up. Granted, I do have a leak in the front of the engine that I'm currently chasing. I also have quite a bit of oil in my airbox. I've read that once that starts to happen it's gg for the duke, is that true? Oh, also, does anyone have a detailed write-up on front main seal replacement? I for the life of me cannot find one.


This is my first time posting on a forum, so please go gentle on me if I've made a faux pas. Thanks


Doggo

[This message has been edited by Doggo (edited 05-09-2024).]

quote Originally posted by Doggo: Hi! I'm Doggo, long time lurker, first time poster. The Fiero has long been my dream car and about a few months ago I finally got my hands on an automatic 85 duke! 122k miles, she runs pretty good, previous owner did a lot of work on her. I've fixed a few things that have come up myself (with plenty of help from you guys lol) but now I've got a problem that I think may do my poor duke in. I'm not super mechanically inclined, so please bear with me. I think my piston rings may be going. The dash oil gauge reads lower than I'd like it to (15-20) but only once she's warmed up. Granted, I do have a leak in the front of the engine that I'm currently chasing. I also have quite a bit of oil in my airbox. I've read that once that starts to happen it's gg for the duke, is that true? Oh, also, does anyone have a detailed write-up on front main seal replacement? I for the life of me cannot find one. This is my first time posting on a forum, so please go gentle on me if I've made a faux pas. Thanks Doggo

it's a timing cover seal or at least that's what I think of it as
pull the pulley off with its 3 bolts and then hope and pray you can remove the center bolt once the crank pulley has been removed and once that is out you can just pry it out carefully and not scratch anything
as for your oiling thing I would make sure the pcv is hooked up since it helps piston rings seal a bit better but it might be game over, depending on what area you live in depends on whether or not you can get a iron duke or v6 easier

Piston rings & most oil leaks will not cause low pressure.

Get a real gauge to test the pressure because dash gauges often "lie."

Oil Pressure Sender can leak & make gauge problems or read 100% right but still leak.
Is why many "upgrade" to 88 sender w/ new plug
See https://web.archive.org/web...rocave/oilsender.htm

Check/replace the PCV valve.
If still get a lot of "blow by" then Rings, valve guides or both need help.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

i will add that the oil sender is excessively hard to get to on a 2.5.even with the muffler removed i could barely reach the harness to the oil sender.

quote Originally posted by richard in nc: i will add that the oil sender is excessively hard to get to on a 2.5.even with the muffler removed i could barely reach the harness to the oil sender.

This make No sense.

I've replace a lot more on 2.5l then the OP sender & had enough room to get @ them from the top.
Sometimes I remove a heat shield on the trunk wall to get more space to remove parts.
But often have to work by feel because hard to see w/ Intake manifold & related parts in place.
⚠️ if working w/ the air cleaner off, Cover the screw(s) w/ heavy rag so you don't hit it/them or drop crap in the TBI.

Even pulled valve lifters w/o removing the intake or the alt.
May Need to remove the ignition & OP Sender to clear the cover to get it out.

Does help when have special socket for 88 sender but not very hard to mess w/ that w/o the socket.
Socket is extra long 1 1/16" socket to fit the odd shape.
Example: https://www.amazon.com/gm-o...essure+sensor+socket

Old sender has 9/16" "nut" can get w/ short wrench.


⚠️ Not all things are Metric. Most sensors/senders are "SAE" Treads & tools to install them. (Threads are actually NPT same as any U.S. Pipe parts.)