455 72-75 Weirdest coolant leak ever

Hello everyone I just registered today and this is my first ever post on any forum for me in my whole life. This coolant leak is sooooo weird I can't find my solution anywhere, so here I am coming to talk with the real Buick buffs.


I noticed on my new 1970 Buick skylark with a 72-75 Buick 455 big block had an empty coolant reservoir. I checked the radiator and noticed that it wasn't low so I drove a good 200 miles before remembering to fill up the reservoir. Freaking out I checked the radiator and noticed that the coolant has not gone down at all. So I pick up some coolant and fill up the reservoir when the vehicle is cold. Before she even hit 100 in temperature she spat fluids all over the front of the motor. Literally a puddle on my block just behind the water pump. But only what was in the reservoir.

I had just bought the car so I decided I want this fixed sooner rather then later and replaced upper, bypass and lower radiator hose. I also replaced the thermostat housing gasket. Expecting everything to be fine the darn thing did the same thing. Before heating up everything in my reservoirleaks out right behind the water pump into this little puddle area. The water pump and fan clutch are both brand new which the previous owner put on and there where no leaks from the hose or thermostat housing. I have no clue where this is coming from

PLEASE BUICK GODS SAVE ME!!!

seriously though I have stayed up all night the last 2 nights and classic Buick information is becoming so rare these days

-Ken

 

Im on it I'll do this first thing tomorrow morning thank you

 

At first I found coolant around the thermostat housing and thought what the heck I was so careful. But upon further inspection I noticed the leak went up the manifold and collected near this screw, as well as something in the back which I'm not aware of what it is(thin steal pipe going into a larger sensor like screw). It might be important to mention that the leak wouldn't come out until I pumped it up to 15 lbs which the auto zone associate said that it could do unto 16lb hope I didn't break anything. I'm really new to working on a 455 and was wondering if it's common to leak through a screw from the intake manifold. It's the screw on the passenger side closer to the front. Do I need to replace the gasket on the intake or just add something around the screw like lock tight.

Thanks for the help

Ken

 

First off, I'd suggest posting in the appropriate section of the board. This is a section for religious topics, something not found on many online auto forums. Thus the name Help From Above. For help with your mechanical issues, best to post in an engine tech section, or in "The Bench" if you can't identify a section that meets your needs.

 

Not by me, I retired from that job...

 

We moved it to Street/Strip 455 tech.

 

The intake is an aluminum Offy 360, i cant see it leaking from anywhere else near there because nothing is near that bolt and its the highest point in which coolant was filling up into a small puddle area.

Waiting for my paycheck to come in to buy the manual and a torque wrench. Spent my whole bonus buying the car. Just got back from the army so tools are really hurting the bank since im starting all over.

Im actually about to change out the valve cover gaskets because im able to hear the spark plugs on the drivers side. Ill try changing out all the gaskets in that area. Do you suggest any upgrades while I have everything open?

Sorry about the wrong place, thought help from above was a funny way to say when youre fed up and the problem is something weird hahaha, builds off of my being so new... took me 15 min just to figure out how to find this post and get notifications.

As far as the manual is concerned my motor wasnt available for the skylark as far as I know. Previous owner took a 455 motor and a 700-r4 transmission for another vehicle. Serial numbers are how I know its from 72-75. Originally this 1970 skylark had a 350. Which manual would you suggest in this circumstance.

 

I can hear ts ts ts ts on the drivers side quite quiet but enough for someone to notice.could be the valves sucking in air

 

Make sure you don't have any water in the oil too. Check the dipstick and make sure you don't have a chocolate milkshake going on in there. If that's cool, as others have said, you can try putting a little snug up on them in the crisscross pattern. If you use a 3/8" regular ratchet, you shouldn't be putting too much torque on them.

I would not change anything. No use throwing money (you may not have) at something to fix what you don't know for sure.

The 1970-1972 Skylark/GS cars were all pretty much alike. The major stuff was the same though some specs were different due to evolving emissions rules and lowered power. Any of the manuals will give you good insight into your car but I'd probably go with the one for your specific body just for the wiring and plumping aspects.

Good luck and we'll try to mentor you along. Some of us live and breath it and others (me) just inhale it on cruise night when we take our cars out for a spin.

 

In addition to the pressure tester I'd reccomend you pick up a couple small bottles of coolant dye.
They come in bottles about the size of a nail polish bottle and show up under an ultra violet light.
Add these to your coolant, pick up a cheap ultraviolet light or blacklight and in a dark space you'll see
exactly where your leak is.

You also mentioned being near a sensor at the front of the intake. Is it the coolant temp sensor maybe?

 

Pictures of the coolant leak area would be good. Maybe the intake too.

More importantly the Offy intake is not meant to fit the 72 and up heads. It doesn't really cover up the small AIR holes at the top of the heads and it doesn't really cover the center exhaust crossover passage. That is probably why you are getting some exhaust noise although I would think it should be a lot of exhaust noise. You really need a later Edelbrock Performer intake or stock intake for the year of your engine to cover everything up. Or you have to take the intake off and plug up all the exhaust holes. I wouldn't recommend the Offy for any stock/mild build for any reason. It is a torque killer and that is tough to do on a 455.

 

These are the pictures I have from this morning, sorry I didnt get them here sooner it took a while to figure out how to upload them and I have been a bit busy. Want to make sure I dont miss any of these good points so I'm going to answer everything one at a time.

Buick 64203, yes it has headers, serial number 123808 on the passanger side, ts doest really explain it too much in detail, its a short ts kinda like the sound you hear when connecting the battery. like a tick sortah. It gets more rapid as I accelerate and when driving loud enough to hear in the drivers seat with the windows closed, but not overwhelming.

Knucklebusted, nothing milky in the oil but it was quite dirty so I just replaced the oil, Ive only had the car for about 1,000 miles and was surprised to see the oil so dirty. so fast. Then again she was my new baby, so i have been heavy on the pedalit a lot more then I should haha.

Dr. Evil I included an attachment with the image of the metal thin pipe going into the intake in the back behind the carb that I was talking about. Do you really think that would help this coolant leak is traveling all over the place. Was thinking of getting one of those dyes once the leak is suppressed and harder to find(The pressure gauge helped me see it pretty clear).

No Lift, Now that you mention it the fit does seem a bit off, you should see what I mean in the picture where you can see the fuel filter. To be honest, compared to my buddies 460 she is pretty quiet(with just a quick look and listen seems to be running perfect). Problem is, I cant find any information to pinpoint exactly which year this 455 was made. The serial number only tells me that is was a 1972-75 Buick 455, Not a 72 and not a 75 which is hard for me to make decisions I can feel confident about after reading about all of the emissions changes between 72 and 75.


Thank you everyone for taking the time to help me out I really appreciate it!

 

Yep, that is a pretty bad coolant leak. As was mentioned, it looks like someone put the wrong intake on it. Those little holes in the metal intake gasket above your bolt are air injection holes that go into the head. If you use that intake, you need to plug those.

I'm going to say you definitely need to retorque the intake to see if that fixes your leak and if it doesn't you'll have to pull the intake. I'd use a composite gasket and cut the old one up to use as a valley pan. Aluminum intakes don't seal as well with a metal gasket as the stock iron intakes.

As for year of the motor, if the HEI is stock along with those heads, I'm going to say it is either 74 or 75. The motors have the serial number between cylinder 1-3 and the build code was between 5-7 close to the dip stick tube. That's only true if it wasn't decked.

Here's a thread from some years ago with engine/head identification info.

http://www.v8buick.com/showthread.php?256737-455-Engine-Identification