Good afternoon.
Well, I really don't know where to begin with this car. So if you'll endear me, I'll try and keep it short but it's gone over a year!
Had a friend with a 96z who was having trouble with a shop that charged him over 300 for a rad replacement. He said that it was boiling out the overflow. and starting to overheat, sometimes within 5min and then up to a half hour.
He was in a bind and needed a car bad or his fixed.
I went over to see what I could help with. After he got in and fired right up. NO SMOKE or 'bad' noise, idled smooth.
overheated after about 10mins, and you could just watch it climb to 220, 230, 240.. But you couldn't smell that "HOT" smell or hear light 'crackling' or see any light smoke off the engine. You could even put your hand on the intake.. Hhmm? (usually you can feel the heat off a motor that is 230 without touching it)
Well I've messed with plenty of the older 350's and thought that the t-stat wasnt opening. after cooling it down, I drilled a couple 1/8 holes in the upper level of it, filled the block from the t-stat, buttoned it up and started again.. Same thing. But this time I noticed the upper rad hose expanding. (didn't think to look at it before)
Ah, it's pressurizing the cooling sys I said. "That's what blew your tank. It wasn't the overflow" cracked the bleeders and steam shot out for about 7'!

It jumped to around a 800.00 job and he didn't have the money to fix the rad.

Well, I've known the guy for about 20yrs and tried to help him out by buying it off of him so he could get another car to get to work and back.
He sold it cheap and I thought to myself that "I've worked on dozens of 350's, I can fix it and resell it" to which he wasn't upset with.
Well life happened, hurt my shoulder, was on light duty for months, finally had surgery but still couldn't reach out over a fender like I used to.
After that, I had saved up a little money, got a set of heads on Ebay (Person said they were checked out fine, my shop checked and said same) Had same shop rebuild them and got in touch with a local shop to do the work.
I told them NO HURRY! which I wasn't.. Plus, for 400.00 I thought it's worth it so I don't hurt the shoulder again. I supplied those heads, bolts, head gaskets for them to use.
3-months later I stopped by (they can say ANYTHING over the phone..) and it looked like the young guy doing the work had been 'cleaning' one of the heads that came off..?? First big red flag! I asked for them to get them checked out and he did reluctantly/slowly. (I thought to myself, I've known them for over 15yrs.. They wouldn't screw me..?
Well after talking to the owner, he said that yes MY heads were swapped but it's still overheating.. He stated that "it's probably the block".. CRAP. There was NO water in the oil, NO white smoke before I brought it to him. Actually, it ran fine except for the overheating.
NOW WHAT TO DO?? I picked it up and asked again if MY parts were put on.
Yes again.. Got it on the trailer and home. Couldn't look at it because of time and piddled with it Friday. I took off the D/S valve cover to see if it was my head(s) (Pardon my rant.. You would think that a multi-BILLION $$ corp could make readable casting numbers/marks!!!! NOT IT THE 30YRS THAT I'VE WORKED ON THEM)
HOW MANY aluminum reverse flow heads did they make? Could barely make it out. 643 or 848 DANG IT!
Well, now it's making a grinding noise either the alt, power steering pump, or non-working air cond compressor that is NOT going with engine RPMs.
And water in the oil!! Although slight, it's in the OIL.
Maybe It's just spilled down the holes from when they pulled the heads.. and didn't change it.

I'm too angry to call right now but don't even know what actions I can legally take. Most instructions were verbal.
Like I said, I've known them for over 14yrs but money is money and friends are friends..

I'm at a loss.. I really don't want to spend more money on this thing that I only wanted to get running and sell to someone who loves and knows them.

Should I try and re-torque the headbolts? They are new torque to yield ones. Can this be done?
Anybody want a rust free Z28??

I need to take a walk.. Errol

 

if u think it just spilled in the oil an oil change will tell u that. but sounds like something going on with the head gaskets or maybe wrong heads or cracked. and for the over heating from the begining, sounds like ur stat wasent opening or a temp sensor. could of not been bleed to let the air out to or nasty clog and needed a good flush.

 

In a situation like this nothing is better than checking it out for yourself. Get a cooling system pressure tester(Autozone loan-a-tool) and see if the cooling system will hold pressure. If not, you are in trouble.

If it doesn't hold pressure, then I would pull the engine and check out the heads and block deck with a known good straight edge.

 

Thanks for the ideas. BUT, I really just wanted to 'fix it and flip it' to pay down a debt.
I don't think i want to pull the engine (but if it were my dd, I most likely would)

I'll tell ya what happened today..
Woke up early got over to the local Chevy dealer and got the sensor in the pump, T-stat and they didn't have the cap. (On order for tomorrow morn)
Came home and got right to it, Replacing deteriorated vacume lines, pulled the condenser (air don't work either)..
Wanted to put manual temp gauges in but couldn't find a good port that I wouldn't have to take out something major to install.
The rockers sounded a little loose to my taste so I turned them all about a 1/4 turn. There was the tell tale tan cream under the d/s valve cover but none under the pass side. (HHhmm)
Had the serpentine belt off so I could spin every pulley to see which one might have been making that growling noise.. NONE??
The air clutch sounded just slightly loud but not like the noise that was before..
So I re-installed (is there a smaller belt that deletes the air compressor and keeps everything else??)

Got everything back together and cranked her up. Fired up on the 2nd turn, Idled better and again, a slight exhaust noise but not bad and NO SMOKE of any kind.. Just a little ticking of the rocker on the P/S that I didn't get to because it was tight already (should have manually turned the engine over eh..?)

Kept it at 2000 for a few mins to help warm it up and got out to loosen the bleeder screws. Little water then stopped. Opened cap. topped off and tightened screws (topped off right??) NOPE, watched the temp climb over a few mins, 160, 180, 200 (no fans YET) 230, felt the hoses, not that hot. Intake wasn't warm either. Kinda tapered off temp wise and thought that maybe i beat it.. NOPE, cracked the bleeders and steam just came out of the upper one (by the alt) Not like a "Steven Segal" Movie but steam nonetheless. But the lower bleeder by the pump NOTHING was coming out as it's wide open..(?)
Got to the last hash mark before red-260 and stayed there for several mins. Fans FINALLY came on but wasn't anywhere near the temp showing on the gauge. Even turned on the blower to max but to the heat side.. more like ambient air temp coming out.

I figured that with the steam coming out that I could undo the cap.. Well, Warm water gushed out.. NOT hot scalding, just warm.
(I wonder if I could extend the wires and route the sensor to other side head and put a gauge in the D/S..?)
NOW WHY THE HECK IS WATER GUSHING OUT THERE, BUT NOT THE BLEEDERS?
It's still pressurizing the system somewhere!
Temp gauge shows RED but I can still hold the hoses.

Well, that's it kids.. Had to run off to work to type this to ya. I'll be here all night so let's hear some advise or offers even..

P.S.-- Could one pull the head without taking the intake off? I mean, I looked at it and if there isn't the little dowels, It could be slid out..??
OR, just loosen the intake slightly to raise it so the head could come up over the dowels. Waddya think?

Errol

 

Thermostat? I know, too easy right. I only say that because you are holding the hoses and they are cold. Just seems weird to me that no HOT water is coming out and the heater isn't doing it's thing. If it's really overheating and everything else is working super hot water should be gushing from that mother. Good luck,

Larry

If you do try a thermostat, get a Fail-Safe. They will lock open if the temp gets crazy. After you run it and see what's up you can check the thermo to see if it locked or if everything did what it was supposed to do.

 

1) MAKE SURE the 2 small hoses on the filler neck are not reversed.

The one coming from the steam pipe on the engine should go on the bottom.

The one from the overflow should go on the TOP.

2) Learn how to properly bleed the coolant system.

 

Is the water pump working?

 

Are you sure you are filling up the cooling system correctly?

You don't want to open the bleeders with the engine running unless the system is completely full(even then...I feel it's not necessary when filled correctly). It has been my experience that if opened with a half full system the bleeders suck air into the system.

• Protect the opti from water and coolant
• Make sure the coolant reservoir is filled to the full hot level.
• With the engine stone cold, open both bleeders.
• Fill the system until water starts steadily coming out the thermostat bleeder.
• Close that bleeder.
• Leaving the one on the top hose open, fill the radiator completely full.
• Put the cap on the radiator and close the top hose bleeder.
• Fire up the car, turn the HVAC heater fan wide open and set the temp to max hot.
• Let it warm up(rev the engine once the temp is above 180* to circulate the coolant).
• Shut the car off once the temp reaches around 220* and let it cool completely down.
• Once cool, check the level in the radiator....you most likely will have to top it off. When topping off the level, open both bleeder screws while filling it(engine is off).
  
• Repeat the warm up procedure, let it cool, and check the radiator level again.

Your thermostat should look like this....with 180 stamped on the bottom(if it's a stock LT1 thermostat).


It does not look like a conventional SBC thermostat.

 

Agreed....check this too.

 

I would not attempt to remove a head with the intake on the engine. You are also going to have to remove the steam tube bolts from the back of the heads too. Dowel pins are present to align the heads to the block.

 

One other thing....if you are letting the temp get to the red...you risk warping the heads. I let mine do that one time and the heads warped on me around 0.003. It was bad enough to cause me cooling problems. I had to get the heads decked to solve the cooling issues.

 

The intake has to come off to remove the heads.

Test for exhaust gases in the cooling system.

 

Thank you guys n gals(?) The head removal was just a thought (not a good one at that)
I just can't accept defeat when I KNOW that I could most likely fix the thing..

Yes the pump is only 2yrs old and circulates very well. And the t-stat is correct.
The thing that was getting to me was that the GAUGE showed 3/4>>-HOT but the intake and valve covers weren't.. I could've held my tongue on it and not been injured.
(just a expression guys.. I DON'T LICK ENGINES!) That's why I don't think that further damage was done.

Ace- I would think that you would want to 'bleed' off the air while the water is flowing (warm) and that it would suck or condense while cooling. Maybe that works better on the earlier motors..?

I'll mess with it tonight after work, and follow your directions.. Another thing is that last night I ran out of time to read up on the Hyper-tech programmer and see if I can adjust the fans through that.

I listed on Craigslist and had two calls before I got home and a young gentleman is supposedly coming out tomorrow morning for a hopeful purchase.
Everything has been stated to any prospective buyers of what has been done or currently an issue.

I'll try and get whomever takes it, to register and be a part of your helpful community.

Thanks. errol