454 Losing Coolant

[Mark E.]

While in storage the past two years, the coolant level in my 1970 454 dropped. A couple of days ago I topped it off (about a quart low) and now the level is down a couple of inches yet again. Also, the crankcase level is higher than before (now above full) so it appears to be gaining fluid. No external leaks seen and the engine has not been started during this time.

I suspect the intake manifold or a head gasket is leaking. Any other possibilities?

How can I isolate the problem? I'd like to avoid removing the heads if the intake is the culprit.

[Mike T.]

Re: 454 Losing Coolant

Mark - Let's hope it's just a matter of a leaking hose somewhere. This is the kit I use to rule in or out combustion leaks into the cooling sytem.
I bought this years ago from NAPA I think but similar kits are available from lots of the auto parts vendors.
You fill that vial up to the line with the dark blue fluid. Get the engine up to operating temp and then put the rubber cone down into the fill neck and use the squeeze bulb to draw up the vapors from the warmed up coolant and the bubbles will come up through the blue liquid. If there's any combustion leaks present, the fluid turns yellow-ish. On a car with an expansion tank like earlier Vettes, the fluid level is typically low enough that there isn't any splash up on the vial but if you have a radiator and the fluid level is close, they recommend draining it down a bit to ensure that only vapors, not actual splashing liquid, get drawn up.
Don't know why some of my pics post up sideways. I've even tried to counteract that by having them turned to the side up front but still it makes no difference.
DSCN6489.jpg

[Mark F.]

Re: 454 Losing Coolant

rotated...

DSCN6489.jpg

[Mike T.]

Re: 454 Losing Coolant

Mark - Thanks and...how'd you do that? I right clicked on the actual posted pic and 'nothing'.

[Mark F.]

Re: 454 Losing Coolant

Mark - Thanks and...how'd you do that? I right clicked on the actual posted pic and 'nothing'.

I right-clicked on your image and "saved image as" with your file name onto my desktop.
I opened it and tried out Dan Adie's suggestion to use "PAINT" to rotate your image 90 degrees to the right (here's his post #16 link):
https://www.forums.ncrs.org/showthre...806#post920806
then I saved it after it was rotated and then posted it back in your string...

You can do the same thing in Office 365 Word and Excel, too as I posted in #13 in that same string - but Dan's method is much more straightforward and does not require the extra step of pasting the image into word or excel...and then rotating
thanks for the tip, Dan !

[Mark E.]

Re: 454 Losing Coolant

Mark - Let's hope it's just a matter of a leaking hose somewhere. This is the kit I use to rule in or out combustion leaks into the cooling sytem.
I bought this years ago from NAPA I think but similar kits are available from lots of the auto parts vendors.
You fill that vial up to the line with the dark blue fluid. Get the engine up to operating temp and then put the rubber cone down into the fill neck and use the squeeze bulb to draw up the vapors from the warmed up coolant and the bubbles will come up through the blue liquid. If there's any combustion leaks present, the fluid turns yellow-ish. On a car with an expansion tank like earlier Vettes, the fluid level is typically low enough that there isn't any splash up on the vial but if you have a radiator and the fluid level is close, they recommend draining it down a bit to ensure that only vapors, not actual splashing liquid, get drawn up.
Don't know why some of my pics post up sideways. I've even tried to counteract that by having them turned to the side up front but still it makes no difference.

Thanks Mike.

No external leaks found.

It sounds like you're suggesting to test for combustion gases in the coolant- if present then probably a head gasket is leaking; if not present then coolant is getting into the crankcase another way. Is this the logic?

[Mike T.]

Re: 454 Losing Coolant

Mark E - Yes, that blue liquid tests for presence of combustion gases so let's hope it's not a positive test. If it does turn the liquid any lighter color (typically greenish-yellow to brighter yellow), then it's time for more testing to figure out what is wrong.
Mark F - Not sure what system I've got on the desktop computer but I might not still be doing this right. I did the right click on my 'sideways pic' and then opened it and again, right clicked, and all I saw was Edit with Paint 3D. Clicked on that and it just sat that saying 'Please Wait - Opening File". When it finally posted, there was no Rotate Command to be seen. Obviously I took a wrong turn somewhere.

[Mark F.]

Re: 454 Losing Coolant

Mark F - Not sure what system I've got on the desktop computer but I might not still be doing this right. I did the right click on my 'sideways pic' and then opened it and again, right clicked, and all I saw was Edit with Paint 3D. Clicked on that and it just sat that saying 'Please Wait - Opening File". When it finally posted, there was no Rotate Command to be seen. Obviously I took a wrong turn somewhere.

Mike,

I started w/ whatever image had ended up in your 1st post w/ the sideways image.
that's what I right-clicked on...so maybe if it came off your phone camera (or regular camera ?), if it ends up sideways when you post, try to fix it from the image that ends up in the NCRS post...I just did it again on your original image and it worked using "PAINT" to rotate it...hope that helps

[Mark E.]

Re: 454 Losing Coolant

Any other methods for determining if this is a leaking head or intake? Ideally without starting the engine?

And if it is a cylinder head, is there a way to determine which one?

[Mike T.]

Re: 454 Losing Coolant

Mark - There's a similar thread currently running over on the Corvette Forum. C2 New Problem, need help!!! - CorvetteForum - Chevrolet Corvette Forum Discussion. Check it out and scroll down to post #13 where he mentions the spark plug in a cylinder that's seeing coolant intrusion would be cleaner than the rest, sort of a steam clean thing. The main difference is you haven't been noticing any white smoke from the tailpipes yet, correct? Have you had the chance to pull the plugs yet?

[Mark E.]

Re: 454 Losing Coolant

Mark - There's a similar thread currently running over on the Corvette Forum. C2 New Problem, need help!!! - CorvetteForum - Chevrolet Corvette Forum Discussion. Check it out and scroll down to post #13 where he mentions the spark plug in a cylinder that's seeing coolant intrusion would be cleaner than the rest, sort of a steam clean thing. The main difference is you haven't been noticing any white smoke from the tailpipes yet, correct? Have you had the chance to pull the plugs yet?

No issues with coolant loss when the engine was running two years ago. It hasn't been started since but it's losing coolant.

[Mike T.]

Re: 454 Losing Coolant

Mark - and when you pull the dipstick, no milky looking fluid or maybe coolant sitting on top of the oil?
And, just to make sure I'm following the story, since the two years of storage, other than noticing the drop in coolant and
rise in engine oil, it hasn't been started at all?

[Mark E.]

Re: 454 Losing Coolant

Mark - and when you pull the dipstick, no milky looking fluid or maybe coolant sitting on top of the oil?
And, just to make sure I'm following the story, since the two years of storage, other than noticing the drop in coolant and
rise in engine oil, it hasn't been started at all?

No coolant evident at the bottom of the dipstick. But the fluid level has increased well above full. If there is coolant in the bottom of the pan it may not be visible on the stick. I'll confirm by draining the crankcase but I'm confident this is where the coolant is going.

The engine has not been started in two years. At that time it ran great with no fluid loss.

[Mike T.]

Re: 454 Losing Coolant

When you do drain the oil, if you do find a lot of coolant added in, unfortunately, there might not be any need to bother with the Block Tester kit. When my Dad and I bought our 66 L79 Mosport Coupe back in '89, it ran okay, nothing great but just okay. Had other things to tend to like work, long commute and other projects so the Coupe sat for about 5 years in my Dad's garage. It got fired up and brought up to operating temp every few months but never driven. After 5 years, we started it up and now it sounded god-awful. Then and there we decided it was time to tear into it.
When we got it over to my garage and drained the oil, the oil came out first and then...this gooey looking 'green' mess followed it. When we tore down the engine, we found the original heads had cracked and in our case, that's how the coolant found it's way into the combustion chamber and eventually down into the pan. I'm hoping that's not what's happened to your engine but for the life of me, I can't think of any other way the coolant could be in the pan other than a compromised head gasket of a crack somewhere. Do keep us posted on what you find and good luck.

[Mark E.]

Re: 454 Losing Coolant

I'm hoping it's just an intake gasket leaking into the valley.

Is there a way to determine if it's a leaking intake gasket vs. something else?