Highest Mileage Blazer Ever? (And Problems)
 

hey guys,

i own a 1999 blazer 4.3 with 455,xxx miles. Yes, 455000+.

this thing is really a marvel but im afraid its recently developed problems are going to end its long run if i cant get them worked out.


acceleration/idling: the idling is pretty rough. it does not cut-out but every once in awhile i feel like it wants to.

under acceleration the engine has a very underwhelming power band especially going up hills. i can feel the engine lose power and the exhaust will increase with black smoke.
if i keep the engine throttled at the same level, the rpms will slowly increase and the power will return. when the power returns, the exhaust will stop smoking. this is a huge obvious pain as i have to watch my sideview while accelerating up a hill to regulate how much gas i give it as to not gas the car behind me. ^_^

squealing: the engine has started to squeal like hell when started cold. as i drive and the engine warms up, the squealing will subside almost entirely. if the engine is warm and idling, the squealing cant be heard.

black exhaust: a soot or some kind of black liquid (oil?) comes out of the exhaust. not a lot, but if i idle for a long time in the driveway, i can see it on the ground. this along with the black exhaust i mentioned above, i thought might be worth mentioning.

oil: the used oil comes out solid freakin black. ive been using nonsynth high mileage oil and a high mileage filter. maybe that normal though?

coolant system: yup its starting to overheat. im thinking a slow collant leak as well, because the backup plastic fluid tank like to stay empty and the overheating problem goes away for a little while when i add more coolant.
i cannot however find a leak. no pools of fluid where i park, etc. no crazy smells either.


as you can already tell, i am not even close to a mechanic. i changed my first spark plugs just last week (girlfriends 06 civic). i am however, not dumb with my hands (emergency responder) so i would love to tackle these problems myself.

any diagnoses of my problems would be very much appreciated! let me know if i can provide any more info...

((im going to change my air filter, seafoam my gas and try my sparkplugs today as well))

ill provide a pic of my dash if yalld like to see my mileage too hehe.

thanks a lot!
cube

Sorry for the double but I should have added: last measured i get around 11 mpg with mixed hwy and city driving.
also, i have to you premium octane gas or the idling roughness gets out of control and the engine drives like crap overall.

thanks again for any advice!

just updating:

i used seafoam 2/3rds in the gas tank and 1/3 sucked in through the vacuum hose extending from the brake booster.
i also changed the air filter and the pcv valve.
the thing is running a lot smoother now. the roughness at idling has dropped waaaay off. the power loss when maintaining rpms going uphill has gotten a little bit better. it still looses some power though and spits some black exhaust.

the squealing is still really bad. might this be a serpentine belt issue? i tried inspecting the belt that wraps around the front of the alternator and cant see any glaring problems... i would really like to get that taken care of.

again, any advice would be appreciated.
cheers.

as for the roughness,pull off the tbi unit and clean out the ports. i bet you thatll fix it since just adding seafoam helped it out. sounds like its just dirty.


as for the squealing remove the belt completely. start the engine for a minute. if sounds gone its a pulley etc. if its still there its something major worn. spin stuff over when engines off. if its smooth like butter its good. any gritty feeling replace it.

as for coolant leak. if you cant find a leak. with the uber super high miles id just add water/coolant and be done with it as long as water isnt in the oil. could be a minor issue,could be a big one. Just toss some water in it every week and drive it.

as for oil turning black,and oily stuff in the exhaust. sounds like rings are getting old and letting bypass gases into the oil etc. Not surprised. just keep oil topped off,or if you wanna spend the money,change it every 1500 miles.

Sounds like engines tired. Id just drive it untill it dies.

thanks chris,

i found the coolant leak, kind-of. it only leaks when the truck is running, a pretty steady leak coming down from right behind the radiator (it seems). the leak stops when i turn the truck off.

ill check out removing the belt and cleaning the throttle body intake as soon as i have time, maybe next week.
im going to have to look on the forums some more though as im not sure how to remove/check belts or mess with the tbi without running the risk of screwing something up.

thanks for your reply

Ok,when i responded i thought this was a first gen,with the old carburetor style injection systems,ignore me telling you to clean out the pcv ports etc.

Remove the idle air control off the throttle body and clean it. even better :

Now you know how to do it. grab you a can of brake cleaner, and a toothbrush. and spray some on the piston looking thing on the sensor. youll see what i mean when you remove it. also spray some in the hole the sensor goes into and scrub it,spray it some more,then hook it all back up. Dirty crusty iacs can cause all kinds of running issues at idle. Also,open the throttle plate and clean around that too.