Olds overheating question

[OldsReliable]

I have a Delta88 with a Y 307, roughly 300.000 miles and no mods.

Lately, I can barely drive the car around the block without white smoke or steam (I can't tell) coming up from both sides of the engine, roughly where the heads are. (Oil, coolant, everything else is good).
I put an open breather element on in a while back and I noticed a lot of the little vacuum lines are basically AWOL. Only one or two are connected to the Q-jet. So are also the hoses that connect from 'the sliver things' that connect to where the sparkplugs are.
My question: Could this be the cause of the overheating? Other than that, I can only blame blown gaskets, heads or worse, block.
It's just my little "mess around with" car, but I"d hate to see it go. Any thoughs, please?

[T-Type]

Lately, I can barely drive the car around the block without white smoke or steam (I can't tell) coming up from both sides of the engine, roughly where the heads are. (Oil, coolant, everything else is good).

From this description it sounds like you are leaking coolant from head gaskets. It could be blown gaskets or warped heads. The real overheating cause may be something else, but at this point it is leaking from the heads. You are looking at at least pulling the heads off the motor. At 300k a full rebuild would be a very good idea. If you don't want to spend that kind of cash, an option is a used motor. Otherwise it's time for the junkyard in the sky.

The vacuum lines (or lack of) wouldn't cause overheating, however it would cause driveability problems.

[OldsReliable]

I think you may be right...
I just realized that my coolant is basically, well.... "milkshake" for a lack of better word. I guess somewhere in the head/gasket/manifold something area coolant and oil meet and mix.
Leak seal (liquid) a good idea? I'm waaaaay to lazy to tear this engine apart....

[T-Type]

I highly doubt a 'leak sealer' would seal a head gasket leak. It's rebuild or junk time (unless you want to see how long it will take for the motor to lock up).

[2002 Caddy]

Originally Posted by T-Type

I highly doubt a 'leak sealer' would seal a head gasket leak. It's rebuild or junk time (unless you want to see how long it will take for the motor to lock up).

X2 these miracles in a can never work. Olds 307 engines are not hard to find at most yards and there is zero "hot rod" demand for them (unlike a small block) so most yards will let them go for cheap (carb to pan <$200)

If you are already making milkshakes then your bottom end bearings have taken a HUGE beating. The engine is toast... and 307s are not worth the cost to rebuild.

Find a G-body cutlass and swap the 307 over. A weekend's project and you will be back on the road for about $300...

When you do the swap replace ALL of the vacuum hoses... Its cheap and will make s huge difference in how the car drives

And once your are done sell the original block for scrap... if your lucky you'll get $50 for it. If it has an "A4" intake manifold that alone will fetch 30-50 on ebay.

[OldsReliable]

Thanks for all the input. I may actually swap the engine out, and I would like a "9" 307 much better. It's just hard to let go...

[2002 Caddy]

Originally Posted by OldsReliable

Thanks for all the input. I may actually swap the engine out, and I would like a "9" 307 much better. It's just hard to let go...

The VIN 9 "HO" 307's aren't all that special... Other then being rare.
Having said that when the sun is out, I park the Caddy and I drive:


You can basically make any 85 or newer Vin "Y" roller cam motor a Vin "9" by simply swapping cams... There are lots of aftermarket grind that duplicate the Vin 9 grind. The rest of the motor are essentially the same.

Of course any Olds nut will tell you if your 307 is toast... A better route would be to swap in a Olds 350, or 403... And while my Vin "9" is still running well... That project is under way too:



If you are looking for Olds tips and tricks for the 260/307/330/350/403 engines... join "oldspower.com" Lots of smart olds faithful guys. Lots of engines for sale or trade and lots of "good ol'boy" types who will think nothing of helping out an fellow olds builder and will ship head bolts or other small bits across the country for free.

If you plan on swapping in a 400, 425 or 455 then join realoldspower.com... The big block guys live there.

[nailhead425]

No matter what you do with a 307, you want the 5A heads.
That later heads have ports that are too small.
Roller cam or not, the ports on the 7 heads stink.

Your specific 307 is sick. I'd at least try a head gasket if it wasn't a smoker.
That'll buy you time to find another engine.

A 350 Olds swap isn't that bad, and they are pretty easy to locate.

Honestly the only place you should go for Olds advise is Mondello.
Joe is an incredible wealth of Olds knowledge, especially regarding building 307s.

[2002 Caddy]

Originally Posted by nailhead425

Honestly the only place you should go for Olds advise is Mondello.
Joe is an incredible wealth of Olds knowledge, especially regarding building 307s.

Joe Mondello is NO LONGER associated with Mondello Performance Products inc. he sold his company and it is now run by some guy named Lynn. Lynn is NOT helpful, NOT knowledgeable and NOT trustworthy

While Joe is still somewhat respected in the world of Olds...
Lynn is infamous coast to coast for being a major rip-off artist.

Do business and take advice from the "under new management" Mondello
AT YOUR OWN RISK.

There are lots of other Olds Vendors who you can trust:
Dave Smith engineering
D!ck Miller Racing Inc
Rocket Racing
BTR

Regarding 307 Heads... For a stock motor both the 5A and the 7A heads are fine...
Yes the 7A has tiny ports... But this is just a 307...

Its actually better not to swap heads on a 307 from a 7A to a 5A... Why?
Well from the factory these motors came with 15 thou thick steel shim head gaskets... GM disco'ed these about 10 years ago. The best you can do is a "custom" aftermarket 28 thou head gasket. Felpro "rebuilder" head gaskets are 40 thou thick. So any benefit you get with head flow you lose in compression. (unless you pay through the nose for a NOS head gasket set)... and this is a 307... Not the best choice for a re-build.

One last point on Olds heads... The Small Block Olds (SBO) motors all had head's denoted with big numbers (the Big blocks used letters). The best flowing (SBO) head are #5's... Thats not the same as the 5A head on the 307... The #5's were used on Olds 350's in 1968/69. They also built #6, #7, #7a and #7A... The 6,7 & 7a were made in 70,71 and 72 and they are all almost as good as the #5... The 7A was made in 1986 and has the tiny ports and is one of the worst flowing head in the Olds family.

[OldsReliable]

Wow, thanks again for all the input. I had no clue so many Olds guys here. I actually joined Oldspower, but I can only read for some reason...

I am also pondering if it is really worth keeping the old 88. The body is everything but straight, but I did give a cool paint job and I just love the boatyness. "Old, not running car" is just not a financial priority right now.

I REALLY like the 68-72 cutlass convertible, but talk about a hard to come around cheap car....

[nailhead425]

Originally Posted by 2002 Caddy

Joe Mondello is NO LONGER associated with Mondello Performance Products.

I didn't realize he sold. It has been about 10 years since he and I talked and I built my 455. He was a class act. I really liked the guy.

Originally Posted by 2002 Caddy

Regarding 307 Heads... For a stock motor both the 5A and the 7A heads are fine...
Yes the 7A has tiny ports... But this is just a 307...

Its actually better not to swap heads on a 307 from a 7A to a 5A...

One last point on Olds heads... The Small Block Olds (SBO) motors all had head's denoted with big numbers (the Big blocks used letters). The best flowing (SBO) head are #5's... Thats not the same as the 5A head on the 307... The #5's were used on Olds 350's in 1968/69. They also built #6, #7, #7a and #7A... The 6,7 & 7a were made in 70,71 and 72 and they are all almost as good as the #5... The 7A was made in 1986 and has the tiny ports and is one of the worst flowing head in the Olds family.

No. For a 307, a 5A is the best bet. Sure you can try to locate some good quality '68-'69 "5" heads, but again, good luck. If you have some spare w-31s with 2.00 intake 1.625 exhaust valves, great. Although, if I had a set, I wouldn't put them on a 307. I'd keep them for a w-31 project, or sell them on Ebay. For most folks, 5A heads are easy to get.

7A heads and 6A heads are small port late model heads.
6As are normally in B-wagons and Cadillacs.

Going from a 7A to a 5A head does cost a little bit of compression, but the ports are much better and the older heads have the same size, or larger, chambers.
For comparison:
5 head, '68-'69 350 has a 68cc chamber;
6 head, '70 350 has a 70 cc chamber;
7 head, '71-'72 350 has a 69cc chamber and the first with hardened seats;
8 head, '73-'76 350 has a 79 cc chamber and is really common.
3A head, '77-'80 350, has a 75 cc chamber, AIR bump, really common.
4A head, 403, 83 cc chamber.
5A head, '80-mid'85 307 67cc chamber.
6A/7A head, 'mid 85-'90, 64 cc chamber, small port.

On paper it is easy to say to some one to locate a 40 year old set of heads that aren't that common, will need lots of machine work, and may be cracked. The older heads will drop the compression the same, or more, than the 5A, the most common heads dropping the compression into the low 7s with stock pistons.

If he needs new head gaskets, then the shim gasket issue is moot.
the 0.2:1 loss in compression is minor for a head swap, especially since the 5A heads flow so much better. 2-3 cc isn't uncommon for a decked set of heads anyway. To each his own.

Oh yeah, all the info I cited, is from Joe.

[OldsReliable]

Let me ask a dumb question: If I change the headgaskets (even if it doesn't stop the leak), should I drive it still? I can physically see where the cooland is leaking onto the exhaust and burning from there, so gasket may not do it. If I keep the coolant and oil fresh, the little white steam shouldn't be a problem, right...?
I am talking about 20 miles trip on the highway btw....

[2002 Caddy]

Originally Posted by nailhead425

If he needs new head gaskets, then the shim gasket issue is moot.
the 0.2:1 loss in compression is minor for a head swap, especially since the 5A heads flow so much better. 2-3 cc isn't uncommon for a decked set of heads anyway. To each his own.

Oh yeah, all the info I cited, is from Joe.

Yes the head gasket are moot if you are swapping heads... The point I was trying to make was you DON'T want to take the heads off of the motor... IF the motor has a leaky head gasket... then get a COMPLETE running motor... and stab it in. A complete running motor 5A or 7A motor will cost ~$300 at most yards. (these get no love)

You need to know as soon as you replace the head gaskets with thicker "rebuilder" ones you lose over a half point of compression, you lose lifter preload (Olds motors rockers are not adjustable), and you build a motor with terrible quench... Saddy as soon as you pull the heads on any Olds motor you "should" deck the block to make up for the difference in gasket thickness... and that's going to cost ~$200... Add the cost of the gaskets... and you can see why you don't want to do this.

One more reason not to swap heads... The intake manifold for a 7A motor is different then a 5A motor... Sure it will fit but you will have massive port miss-match issues and it will run like crap... Sure you can start swapping parts... But his goal was to get back on the road fast and cheap...

Fast and Cheap = Wrecker motor swap...

BTW none of the early Olds heads... will work on a Olds 307... The bore is too small and the valves will hit... I only posted all of that in case he upgrades to a 350 or a 403.

[2002 Caddy]

Originally Posted by OldsReliable

Let me ask a dumb question: If I change the headgaskets (even if it doesn't stop the leak), should I drive it still? I can physically see where the cooland is leaking onto the exhaust and burning from there, so gasket may not do it. If I keep the coolant and oil fresh, the little white steam shouldn't be a problem, right...?
I am talking about 20 miles trip on the highway btw....

If no coolant has leaked into the oil (AKA milky oil) AND if you don't mind being stranded then top up the coolant (daily) and drive it...

And if performance is not an issue to you, you can just throw a set of felpro rebuilder gaskets at it and call it a day... But keep in mind you will be taking an already low compression 8.5:1 motor and will be driving it down to 8:1.

[OldsReliable]

Originally Posted by 2002 Caddy

And if performance is not an issue to you, you can just throw a set of felpro rebuilder gaskets at it and call it a day... But keep in mind you will be taking an already low compression 8.5:1 motor and will be driving it down to 8:1.

...which is not a problem since the car is running funny anyway without any vacuum tubes.

Another question (I know, I'll stop): Ever since the engine started overheating, I have MUCH MORE power than ever before. I mean, I have NEVER gotten that engine to rev up these RPMs until now! It's like it finally drives like a V8, but now I can't drive it!!!!

Maybe I'll get a donor 307 one day and have it swapped in. Or a 455...