TAbracadabra

Just wanted to jump in and say Hi and thank you all for your excellent responses.
I've been reading many threads over the last month or so.

At the end of July this year I grabbed ownership of a car I wanted since I was 10 years old. A Z/28 Camaro !!
Better yet it is an IROC-Z !!

I fell in love the minute my oldest son showed me the pictures of her.

She did develop an overheating issue about 3 weeks after I picked her up.
Went to flush the cooling system and replace the stock 195 thermostat with a 180 version.

Wel, that went bad. The rear bolt for the thermostat housing was in fact a stud and even
with liberal amounts of PB Blaster, I thought it was turning and then .. SNAP !!!

The stud broke off. I'm not sure why it was a stud and not a bolt as there was nothing
else connected to that stud after the nut.

Anyways, I am not a newbie to the SBC. At 17 I built a 355 up from a bare shortblock, ported my own heads and dropped it in my '69 Chevelle
replacing the 307.

Now it is many (Many) years later and just for the comfort factor I pulled the manifold
and a shop is drilling the stud out and rethreading it. (+ I don't have all the tools I used to have access to back when I was 17)

I also noticed that the single electric fan never goes on unless I use the jumpered ALDL
to put it in diagnostic mode. So I picked up a cheap kit that I can wire in parallel with the existing circuitry but allows me to set
an on/off temp as well as a manual override switch to run it if I want (For whatever reason).
That should fix that but after reading some threads, maybe it is a bad coolant temp sensor/switch.


I also have this 2-1/2 in thick BeCool radiator and after removing it from the car, soaked it in a prestone cleaner and all this rusty water came out. Rinsed it 3 more times through various accessible inlets with a hose and now it is clear.

Also in another thread I read about the lower air dam/chin spoiler that directs air into the radiator and guess what !!
Mine is missing. I may fab one up temporarily but would like to get the one that belongs there. Any suggestions where I might find one?

Hmm, Which brings me to another issue. When the temp, per the gauge, is about 240F my oil pressure drops to about 10-15 psi per the gauge.
In fact, Once after a couple of runs at 125 MPH the oil pressure dropped so low it seemed like the fuel pump (or spark) turned off and the engine turned off !!

I am hoping that once I get the temp issue resolved the oil pressure issue will go away as well.

There is no tapping or any other strange noises coming from the engine when the oil pressure drops. The 305 only has 105K miles on it.

The oil pan is dented upward (3/4 - 1 Inch) though which makes me wonder if there is enough clearance for the oil pickup to work effectively or
the pickup tube may have a small split and might possibly suck air when the temp gets really high (Thereby causing the viscosity to drop)
(Thinking the 5W-30 Conventional is thicker at the lower temp and may not be as susceptible to air draw ?) .

Thoughts?

Thanks, Tim

dlinger

iTrader: (4)

How was it overheating (was it boiling over)? Driving at over 45 mph or under, idling?


I was able to find one at Chevrolet dealer, but that was 3 or 4 years ago.

Did it drop to 10-15 at idle or driving?

Both our 84 and 95 will run a constant temp around 190 at highway speed. Once they start idling temp will rise until fans kick in which is around 220 (my 95 has two fans, one kicks in then other when temp gets even hotter or AC is turned on) After idling and cars get back to highway speed, temp goes down to around 190.

When I first drove our 84 home, temp was around 100 and no air dam, car kept running hotter all the way on highway. Air was not flowing good enough with out the dam to cool it. After installing new air dam (and new radiator, pump, thermostat), anything over 45 mph, air movement keeps the car at thermostat temp. Below 45 mph fan takes care of cooling car.

TAbracadabra

Thank You dlinger for responding.

Overheating per gauge only (245-250
and oil pressure drop (5 PSI), again per gauge.
Was not boiling over but was very hot under the hood/hose temp.

---

Thanks !!! I checked with a local Chevy dealer and even now in 2016 he says plenty
air dams/redirector underbody airflow to A/C condensor/radiatior available.

I picked a new one up from the dealer yesterday

---

@Idle. Had the car out for a run and then stopped in a convience store so she sat a for a few minutes. (Heat Soak?)
Tried to leave the lot and anytime I let off the gas and it went to idle, it would shut down.
(And also had ~ 5-10 psi oil pressure per the gauge at idle).

Just got the TPI lower manifold, runners and plenum back from the machine shop (Had the whole TPI system glass beaded, Ported !!, and hot tanked).

Looks absoutely beautiful !!
In process of putting it all back together with a 180F thermostat and cooling system flush.

I'll update when I get her back up and running

Thanks,
Tim

TAbracadabra

FYI in case it can help anyone: Front lower air dam,

Description: Deflector
PN: 14083929
Application: 1986 Z/28 and IROC-Z for sure.
May fit other applications/Camaros or Firebirds - Ask your dealer/provider.

Retail is about $70, Business to Business is less (Typically they need your Federal[FEIN] and/or State Business Tax ID#).

Hope that helps,
Tim

dlinger

iTrader: (4)

Sounds like car after driving at speeds excess of 45 then idling heats up to above 220. The lower deflector will help lower cars temp while driving at higher speeds.

Like I mentioned driving ours home the first time I had no deflector (Chevy gave me the wrong one) and temp was over 100. Temp rose over the 100 miles stretch to about 220. With deflector, temp stays about 190.

When you stop driving above 35, temp should rise to about 220 (without air on) then your electric fan should turn on.

The higher than normal temp possibly could be causing the lower oil pressure. I would make sure that is working properly. If then you still have issues, I would bump up the oil to 5W-40 (if they make) or 10W-40.

TAbracadabra

Seems the Air Dam/Deflector makes a big difference.
A 350 will heat up even faster w/o the air dam but when in place the air dam lowers the temp to ~200 on the highway. Still fiddling with the 305 and the suspension/steering/brakes but I expect the same difference when I test that combo over the next 3 days (After the 305 is RTG (Ready to Go))

Oil pressure was OK at 220 F engine temp (via Gauge). Going to pop out the the knock sensor to help drain the block and re-flush the cooling system as well as change the oil and filter over the next few days.

** New related Question:

I am also planning to add a themostatic control to wire in parallel with the stock fan circuit so
the fan will come on for short intervals even when the key is not in/in Run position. But I do
have a concern that I don't want that added fan function to kill the battery - Just want to minimize
"Heat Soak" conditions. (Run it awhile, stop and turn the engine off, temp builds as no coolant flow, return to a very hot engine).

For instance, Is there a controller that monitors the input voltage and will not let the fans run if the
battery supply voltage drops to low?
I currently have a Hayden Automotive P 12623-IS(Rev 3/00) 8006203 Fan Control on my shelf ready to install/mod.

Would that work with a method / parts added to insure the battery does not get run down or should I maybe consider
a more expensive fan controller that might include/be more adaptable to the anti-battery run down feature?

Thanks,
Tim

Jay_rich

iTrader: (4)

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