Alright guys, im officially stumped, the other day my 66 chevy c10 sportin a 262 straight six started whistling while driving, sometimes a little bit, sometimes super loud, usually louder the fast it went and while slowing down. The water temp was normal oil pressure was normal, then a few drives after that i noticed the water temp was pretty high, and after pulling over it was dumping coolant , but the coolant looked like chocolate milk, brown and oily So then I pulled dipstick and a plug and both were normal, clean oil I was pretty baffled then but decided to flush the coolant and see what happened, so i flushed out the coolant, checked the timing, double checked the valves, and carburetor. After doing all of that I drove it maybe for 20 min and return to flush the coolant flush out, it barely came out, pulled the hoses and they just oozed oily coolant, like icecream, cleaned it all out, flushed it again, then filled it up with water and drove it for 20 min to again to flush the system, get back and again tons of oily coolant clogging everywhere. Keep in mind the water temp stays at normal through all of this, I dont see any rust in the radiator, and still no coolant anywhere in the oil. Figured id do a compression test to see how that went, I've heard you can tell if a head-gasket has gone by low compression, but all the compression was good, around 160 psi in all the cylinders. And now im really dumb- founded, is the block cracked? Where is this oil coming from, also oil level is fine too. Im stumped, anybody have any suggestions on what to do next? Im ready to pull the engine and replace seals and gaskets but don't want to do something that isnt necessarily going to solve the problem
Sounds like a head gasket blown between water and oil passages to me. Posted using the Full Custom H.A.M.B. App!
I had a 63 6 cyl 230 and it had a crack in the main galley into the water jacket, I don't know if the 292 had a similar problem but I was told it was not uncommen in the early 6's. it was small enough that oil pressure would push it out but tight enough that water would not go in the oil.It was a wagon we used as a shop truck,we would syphon the oil out of the radiator and keep going it was a heavy yellow grey color.Eventually put a 327 in it.
Yea im really worried about finding out the block is cracked somewhere, I am going to pull it over the holidays and see what I find, thanks guys
Yea I'm pretty sure that's what you are going to find, the Chevy six doesn't have oil pressure going through the head gasket.
We built a bunch of 230 & 250's for racing on Long Island and the block casting on anything before 1969 were prone to cracking the oil passage that runs from the front to the back, this issue may also bei common to the 292 as the casting from the lifter area down is very similar. The blocks would not have had the problem when they were in the street vehicle but once the engines get stressed by running it hard they would spring a leak.
Most likely a cracked block. I had a similar problem to what Hotrodbuilderny had on a 250 many years ago.
Back in the day, when I worked on lots of 292 engines in trucks, it was somewhat common to have blocks crack in the lifter bore/oil galley area.
So before you pull the engine could you pressure test the cooling system and look for coolant in the oil?
There was no coolant in the oil, i have drained it completely and there was a ton of oil in the coolant and no coolant in the oil, im pulling the engine next week, if its just a head gasket im hoping for that or a cracked head then replace that, needs new gaskets and seals all around anyways so gonna address all that as well
Alright guys a couple of new questions... Pulled the head and found a large compromise in the head gasket. Also had the block and head tested and everything checked out so that was the problem. I have rebuilt everything and just about ready to put it back together. I have a few questions tho... I am going to replace the freeze plugs for brass ones while the engine is out, I know that in order to replace them I need to hammer them out and pull them out, but the one that looks like it is at the end of the camshaft, do I remove that the same way or will I just be hammering it into the camshaft? The repair/service manual doesn't say anything Also I noticed that where the smog tubes would connect to head there are small screws with tubes like this in the head... Since I am not running any of the smog stuff can I just pull these tubes out and then plug the holes back up?
I think you are going to be sorry,oil does not run through the head under pressure, how would a compromised head gasket allow oil into the Radiator?The reason the oil goes into the radiator and not the other way is because you have 30lbs of oil pressure or better.compared to 10 12 lbs. I have been through it, and my fathers partner use to be a service manager for a Chevrolet dealer back in the 60's early 70's, and it was not uncommon for them to crack.Not all but there were a few.I don't know how you can pressure test the oil passages but I would be leary.
As to the cam plug, drive it out from the front unless the cam is already in, if it's in you can take a screwdriver smack it through and then pry it out. Yes you can remove the tubes and put plugs in.
Not sure the gasket was seriously destroyed right through the coolant passage on the head, if the issue continues then your right I will be pretty bummed, but I had a blast rebuilding it and learned a lot, but I had the head checked and the block checked by a reputable builder here in california and mentioned that and he said that because the leak was from the cylinder to the coolant passage that the water going into the cylinder was burning off before going into the oil, we did find some in the oil when we drained it out but not a lot But thanks on the other info, I just wasnt sure the clearnce behind the camshaft plug if it would hit the camshaft if I hit it in
So without fail, it has been almost a year after rebuilding the motor we took it on a trip to AZ and back and after getting back I noticed again there is oil in the coolant, so clearly we have a cracked block, it is a bummer because I thought we were in the clear on this one, spent a lot of time driving the truck around without any problems. So I think we all well know the block must be cracked, is this something I assume cannot be fixed so I plan on picking up another 292 long block. My question at this point, is this a fairly common problem? Should I be nervous about the block I buy also having a crack somewhere? We had this block pressure tested and it passed so I would not want to do another rebuild and have essentially the same results.
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