My 1993 351 bronco has 75,000 miles on it, which i bought used around a year ago. Anyway my problem is that a few months ago i started getting really bad excessive blow by . It would come from the breather hose coming from the oil cap area into my air filter. The blow by happened all of a sudden though, not gradually, which was weird. So i took it in to get compression tested and they said compression was good. I dont see how my engine could have gone bad in this situation, could there be anything i could do like replace the head gasket before i go in for a rebuild. Thanks

 

Check your PCV valve (just replace it) and the hose to it.

 

My wife taught me something about 5 minutes ago "you don't get rid of the puppy just becaused it ****ed on the floor" what that has to do with your Bronco, I don't know? Do what andym said, chances are it is a very simple problem. Good luck.
Al

 

i already changed the pcv valve and the hose. So i am still at a loss? Any more suggestions? Thanks

 

Could be a cracked piston oil ring, you would get blowby all of the sudden and the compression would read ok.

 

if you have blow by coming from your oil cap it is broken rings it happened to my 79 f100 that i put a 351w into i over reved it is the best that i could come up with ,but none the less when i ripped it apart it was a bunch of broken rings

 

Yep, broken rings. I presume you checked the braather in the air filter when you changed the PCV valve.

 

If it is broken rings, would that have screwed up my engine for running it for a long time with the bad blow by. Also any tips for tackling this problem? Thanks

 

The oil will contaminate and break down sooner. They will score the cylinder walls in many cases. Basically a short block rebuild @ 75,000 miles if you're going to take it down far enough to do the rings. You will be far ahead if you do it.

 

If you bought it used, the old owner my have not done the Bronco any good !!!! Just a try if comp. is ?? try Seafoam in the vac booster line. First let it run & get to normal temps. , put it in the vac. hose with it running & stall the engine with it let it sit for 20- 30 mins. to soak in to maybe loosen the rings if thay are frozen to the piston . When restarting it it will smoke very badly run it for 30 mins. & it should clear up & may help your engine !!!


Don

 

If it has a cracked ring, you can drive it for a while until you get the money for a rebuild or reman motor. Make sure to keep oil in it, and don't use it to go on any long trips... You don't want to grenade the block, because then you won't have a usable core and the cost of repair or replacement of the motor will go up.

I drove an 88 Ranger (see my gallery) with a cracked ring for quite a while. I am not sure how long because the truck was relatively new and had low miles. It wasn't until I checked the air filter one day that I noticed that the breather box had a bunch of clean oil in it. I had actually driven the truck on a 5,000 mile road trip before I noticed it, and I think that the ring(s), not sure how many, cracked on the trip. Since I put a new air filter in before leaving and there was no oil in the breather at the time, I drove for a while without checking the air filter again. The truck ran and drove perfectly but eventually it developed a miss at idle; and that's when I looked inside the breather and saw the oil. At first, I figured that the PCV valve was the problem, the truck only had about 79,000 miles on it; but no such luck, it was a cracked ring or rings. The guy who bought it like that told me later that it was cracked ring(s) but he didn't say exactly how many. It didn't matter anyway. I did not like the truck regardless, I now know that Rangers are junk, and Ranger that only solidified my opinion. And I had sold a sweet 72 F100 (see my gallery) to buy the Ranger because I wanted something newer. Hindsight is 20/20, right?

 

alright thanks for all that info! Would you all recommend a rebuild or a recond. engine? What would be the cost of each for an average shop to do the work? Thanks

 

Could the problem be a screwed up head gasket? Also could i be able to take my valve covers off and see if it is the rings?

 

the only way you'll see your piston rings is to pull the motor out put it on an engine stand take take the oil pan off, then take off the heads & intake undue the rod bolts and push the piston out or just undue the crank & rods

i drove my 351w a long time with broken rings it actually was costing more in oil than gas when i pulled it out i went 200 miles it took a full tank of gas and a gallon and a half worth of oil i was running 15w40 because of the blow by

 

The thing about piston rings is that you have to take the whole engine apart just to see if they are cracked - so at that point you are rebuilding it anyway. Nobody here can say with 100% certainty that you have a cracked ring or rings; but most agree that we think that it is a busted ring. Either way, since the PCV valve was not bad, you have an internal engine problem and it's pretty much time for a new motor.