GQ-ROD

Hi all,

I will begin with the symptoms.

3 weeks ago i was an hour long drive, noticed the oil temp was getting high to me, it hit 250 then 256 degrees.

Coolant temp was low around 180 ( no thermostat installed ).

Bone stock engine no mods.

Changed oil and oil filter as it was due to be changed anyway.

No effect.

Drove again for an hour oil temp maxed out at 256 degrees at 70 mph, oil temp went down as i slowed down to 55 mph to 240 degrees.

Oil level was good.

Oil temps on this car normally have never gotten higher than 235.

Driving home however i see the coolant temps starts to rise fast, got to 235 and oil temp got to 245.

I know 245 is normal BUT that's with a thermostat.And my coolant temps without a thermostat never got above 210

At idle it stayed at 239 degrees on the coolant temp. Fan is working, radiator that i could see is not obstructed, water pump is working, heard no noises from it using an auto stethoscope and i do see coolant flowing in the radiator.

Checked coolant level it was about 1/2 gallon low. I did see little bubbles coming out engine not running as i filled the radiator.

Restarted engine let it warm up at idle temps on coolant never got above 185. Oil temp got to 190.

Now i start to freak out, i wonder if the head gasket is blown?

So got the combustion gas tester rented at auto zone and bought the liquid to test the head gaskets. I'll test it tomorrow.

Also rented a radiator pressure tester to pressurize the system and see for how long it holds pressure.

Doing a search i believe hopefully i may have a bad intake manifold gasket as i see a mist of smoke coming from the rear of the engine at the firewall.
And an oil leak. Car never overheated or boiled over, still running well.

I have the FSM !

Wanted to post this so others can benefit, any advice or suggestions would be greatly appreciated, will keep you posted.

Gibbles

I assume your 84 is like mine and does not have the oil cooler?

Also what weight and type of oil are you running?
Remember you have a flat tappet camshaft in that thing, needs a good high zinc content.

My car can get a bit high in the oil temp the harder i run my engine, the lighter weight of oil i run the cooler the oil runs as well.

All that said, that's not that high of a temperature for oil, i would not worry unless it starts going to far past 300f

Also check the sensor near the oil filter, mine lost much of the insulation and the gauge went a little weird on me.

Gibbles

Also, no thermostat is not good, you need some restriction there.

You can take the center out of an old thermostat for a cheap restrictor, or just drill some holes to allow coolant to bypass.

GQ-ROD

Thank you for your help and advice. I will be installing a new oil temp switch soon as you pointed out i think the insulation is gone on mine as well.

Update so far,

Did the combustion test and thank goodness it's NOT a blown head gasket.

The liquid did not turn yellow or green at any time. Stayed blue, though the liquid from auto zone is a pale blue not a bright dark blue.

Moved onto the radiator pressure test, WOW what a gusher.

Found a coolant leak on the front of the engine area, could not tell where it was coming from, finally found that it's on the drivers side water pump mount.

I could feel the coolant there.

BUT it never leaked on the ground, and i never saw any smoke before so this test is a MUST for diagnosing coolant problems !

The pump seems fine, no noise, no play, it seems the last owner installed it with too much RTV as i could feel it crumbling in my hand.
and the gasket finally gave up.

I will be replacing the intake manifold gasket when i have enough time to ensure i do it right as the minor oil leak is still there in the rear.

But for now i'll be replacing the water pump first.

I will also install a new thermostat. And a few other parts that i'll change since i'm already under the hood.

Thanks again for the help ! i'll post the progress .

GQ-ROD

Forgot to answer you questions.

I'm running castrol 10-40 regular dino oil.

And it does not have the oil cooler.

I'll be installing the thermostat.

GQ-ROD

I have a question and didn't want to start another thread,

The FSM on page 68-7 does not say wether or not to use rtv on the gaskets or the bolts.

Should i use RTV on the bolt threads when installing the new pump?

Gibbles

Be careful on your pump selection, a corvette rotates backwards from a normal small block.
corvette pump should have an aluminum housing and be of a high flow and reverse rotation.

Do not cheap out there.

I have a "be cool" brand pump on mine that i have been happy with, however i had some cooling issues post engine mods, and my car had It's pump replaced with a cast iron standard truck pump that was not great for the car.

And yes, i like to dab some rtv on the threads.

10w40 explains the temperature as well, dont read to much into the temperature unless you start getting into the 350f range.

When driving my car hard at lower speeds, i have come very close to 290f running vr1 10w30.

I was worried about the temp until i did some reading, i found out it's fine...

I also installed a longer filter and wrapped it with heat shield material to insulate it from my headers, that dropped my oil temperatures quite a bit.

GQ-ROD

I ordered the one at NAPA a new one, i see on their site it says it's bidirectional.

I will remove the old pump today and chase the threads and clean the bolts and use rtv on the threads as you suggested.

Will post pics once i make some progress.

I'll get some wrap for the oil filter and do that too thank you !

Gibbles

They all say bidirectional, but usually the hiflow onces should also specify reverse flow.
if it's cast iron reject it, the standard pumps have a weak paddle setup.

Crack the back open before you install, a good one will have a caged aluminium multi paddle wheel.

​​​​​​​If one with the unsupported forks, you will only be asking for issues later on.

GQ-ROD

Ok, manged to get the old pump off.

Everything went smooth until it was time to get the tensioner bracket off.

The fuel lines were in the way, however rather than removing them which would have been a can of worms, i moved them to the side enough, while pulling and turning the bracket up and out and away from the fuel lines.

This was the trickiest part, following the FSM procedure was good, it was easy to stay organized on steps, make sure you install all the bolts into their respective components, ie: when you remove the ac compressor install the bolts into the compressor to keep track of which bolts go where.

The strange thing is the old pump did NOT have any gaskets, it seems the previous owner used 2 different kinds of rtv a white and a black

.

It's a miracle it lasted 5 years.

So now i'll start chasing the threads as a lot of rtv made it a little difficult to remove them, and cleaning up the mating surfaces for the new pump.

Oh i did find that the tensioner bracket was cracked, and someone tried to weld it to no avail.

So either i get a used one or jb weld the cracks.

Gibbles

You can get another bracket off of ebay, however a radiator shop, machine shop, welder can fix that up pretty easily.

Aluminium is easy for anyone experienced with welding it.
I will say to lie when they ask you what it's off of, corvette tax...
i usually go with an old buick...

GQ-ROD

Thanks again for your help, I had to order it, the brand is tru flow, they have a high performance one that does state reverse flow, i may upgrade to that one when i go in tomorrow.

I believe the one i ordered is alluminum but i will check it tomorrow i'll take my old one with me to match it up.

Also a good tip is to take off the heater hose nipple while the pump is on the motor, i used a 24mm wrench on it, don't think i would have gotten if out with the pump out of the car !

Looks like the po used teflon tape and rtv on this what a mess !

GQ-ROD

Good advice thank you ! i'll keep ya posted .

GQ-ROD

Gibbles, good thing you pointed out the cast iron pump to me i looked on napa's web site and it looks like the one i ordered may indeed be cast iron.

So my only choices now seem to be

Oreilly's Murray brand- alluminum counter clockwise rotation.

Autozone Duralast brand- alluminum counter clockwise rotation.

Both have heavy duty versions for double the price which i don't mind.

Napa only offers two new both cast iron only one states reverse rotation,and a re-manufactured unit don't know if it's aluminum or if they rebuild mine.

Not fond of duralast, also don't know about Murrary brand, never tried it.

Checked rock auto but I'm leery about buying this online, I'd rather get it locally in case of any issues.

Thoughts ?

Gibbles

I bought mine from summit racing, not sure about the box stores.
the one i was told to buy was the edlebrock victor jr, i went with the $100 pump instead.
flow cooler if i remember right, and it came with a sticker for my tool box! :p

GQ-ROD

Ok thanks !

I found one heavy duty at advance auto parts, aluminum, reverse flow, by carquest, new.

I did hear from a mechanic that this brand is good no customer returns for parts issues so this is what i will go with as they can get it next day.

thank you again for all your help, will post updates soon.

Gibbles

Big thing is that it specifies high flow and counterclockwise/reverse flow.
​​​​​​​high flow, and it should have the better wagon wheel pump design.

GQ-ROD

Great thanks again !

GQ-ROD

Alright, finally got it all done.

First i ordered a water pump from napa turned out it was cast iron not aluminum, so that killed 2 days.

Then ordered the heavy duty one from advance auto, initially should have been in the next day.

BUT went in and it was not there, SO had to wait again, another 5 days wasted.

Now comes the fun part.

Got it in it's the correct new one, reverse flow, heavy duty, aluminum.

Get it on with the gaskets, waited an hour to toque down the bolts to spec, and all of a sudden CLINK !!!! yeah one of the bolts SNAPPED !

Looked at it and realized the previous owner had installed what seems like a regular bolt, with a nut welded onto it.

So had to take it all out AGAIN !

Broken stud came out with vice grips THANKFULLY i had already chased the threads with a tap.

Looked online and NO ONE has these bolts, specifically the one i needed. LUCKILY found a used set on ebay, ordered them, so now another 5 days wasted waiting on parts.

While waiting on the bolts i installed a new stock capacity radiator, budget is tight. Removed the a/c condenser as i won't be fixing the a/c until next summer.

Installed new hoses, new 195 degree ac delco thermostat i had drilled a 1/8th hole in to help bleed air, and new hose clamps.

Got the bolts in, cleaned the female threads on the block with a 3/8x16 tap which is a MUST DO ! BE CAREFUL, TAKE YOUR TIME, you do not want this tap snapping in the head. Once you feel resistance back it out ! blew out the holes with compressed air !

And cleaned the threads on the bolts.

Put it all together yesterday i only applied rtv on the 2 lower bolts as these are the ones that seem to go through water jackets, waited an hour per the instructions on the permatex label then torqued all the bolts to 30 foot pounds,waited 24 hours for the rtv specifically made for water pumps/thermostat housings to cure and ran it to bleed it.

All seems well, however i still have to bleed it again as it did not seem to get past 195 degrees long enough for me to see if it burped.

Oil temp was about 30 to 35 degrees higher than water temp.

Thanks Gibbles for all your help !

I'll update this thread once i am ready to do the intake manifold gasket.

GQ-ROD

After bolt snapped in head !