CJ-7 Still Running Hot... Help Please!

[kirk211]

Here's a direct quote from an old post. I found it searching buickv8.com and anything else I could find about the Buick 350.

MOTOR, Dang! The secret is out...BUICK 350 engines! [Archive] - THE H.A.M.B.

"BUICK 350 FRONT COVER NOTES:

The Buick 350 usues a big aluminum timing cover which houses the water pump and the oil pump. This casting has a few little qualities of it's own that you might want to be aware of before messing around with one.

First, as mentioned a few replies ago, there are two water pump bolts that pass into the water jacket. Thread sealer should be used on those two bolts at least, to prevent coolant from leaking out of the engine, or into the oil through the timing cover. If looking at the water pump straight on from the front, the bolt furthest to your right, and the one below and to the left of it are the ones to watch here.

Gasket catalogs still list a rope seal for the the timing cover on 350 Buicks, but a Turbo V6 Buick neoprene seal is a direct replacement that works FAR better, and should be on your parts list if your diving into one of these mills. My old machine shop guy turned me onto this trick when I was building the 350 Bucik for my ex-wife's car.

The oil pump can be upgraded to high volume status simply by purchasing a TRW hi-volume rebuild kit for it. It comes with the parts you need to rebuild your oil pump and will increase oil flow. Simply ask your parts counterman for the hi-volume rebuild kit.

Be sure that you check your timing cover over very thoroughly before prepping it for re-installation. They have been known to crack, shift or simply wear out in key areas...causing mystery fluid leaks and other untold headaches! Give your cover a close visual inspection, checking the gasket surfaces for squareness and all areas for evidence of excessive porousity. Seek out a new cover if you have any doubts.

The aluminum timing covers on these engines can wreak havock on some of the bolts that enter or pass through it. Over time, and with exposure to the forces of nature, and heating and cooling cycles, those steel bolts can seize up and break off in the cover, or cause the cover to break when torque is applied to break the bolts loose. I had to have two broken bolts removed from my timing cover after pulling the engine apart! Be aware of this when disassembling your engine, and use an anti-seize compound during re-assembly to prevent such problems in the future.

When rebuilding your oil pump, cleanliness is the key, as well as being on the lookout for excessive clearances. The gears shouldn't wobble or rattle around like crazy when test-fit prior to final assembly. Pack the pump with petroleum jelly and assemble. Tourque the oil pump cover bolts to 10 ft/lbs and you're ready to go!

Buying a new water pump is a common sense move, and something I always do with a fresh motor or when swapping a cam or installing a new timing set into an existing engine. Nothing special to watch out for here...install the pump with your favorite sealer on the gasket and use thread sealant on the two bolts mentioned previously.

Just a few pointers to help you with a potential problem area on an otherwise excellent engine!"

Hey! Could be the 2 bolts on the right side that run through the water jackets! I do remember when changing the water pump that the bolts were pretty nasty looking (wet, dirty water on some), and now I'm wondering if it was because there is a small leak there.

So the plan... I have coolant system flush running for the next few days until my new high amp alternator shows up (another unrelated problem). Once it's flushed I'm taking out the bolts on the right side and putting some thread locker on 'em. Next, gonna run in some head gasket sealer crap in a can because I'm not looking forward to changing out the head gasket and I'm gonna try cheap and easy first.

My hopes are not all that high, and I have a head gasket set coming along with the alternator in the mail. I'll dive into that laborious crap if this fails. I've got a torque wrench and gonna go get the Hanes manual to be sure and do it all in the right order and all that jazz.

I will let you all know how it goes. I guess it's just a design issue with the engine, and this hopefully solves this issue for some of us.

[GeeAea]

I think you should try putting a valve on that formerly routed through the heater core bypass hose. Lots of flow could be bypassing the rad all together. The racing remote thermostat housings run two smaller hoses to each head and you've got a somewhat balanced suction:discharge head in a continuous cycle ..so a "choke" doesn't necessariy mean a true restriction. It's just a point of acceleration of flow.

Anyway, at higher flow rates, the rad can introduce impedence to flow ..while your bypass hose can look like an easier path. At lower speeds, they may appear different.

I think I read every post carefully, but I could have missed this being addressed. If it has, my apologies.

[kirk211]

Where might I get a valve like that? A race shop? That's a hell of an idea, and if it's economical it sounds great.

Just an update.
I ran hot again for the 2 billionth time home today, up to the 230ish range, even on back roads. But as always, stop and go overall tends to keep it cooler even though it jumps up 20 degrees in 5 seconds right when I stop.

So I ran Prestone Flush for about 6 hours of driving time, then hooked up the backflow valve to the T shaped thingy and flushed it all out with the garden hose. No too suprizingly, no real nastiness there. However, the coolant drained directly from the radiator was sorta rusty looking... makes me feel like it did some good.

So I wanted to put this damn water pump BS to rest. I took the stupid thing off again and looked at it, and spun it, and imagined it turning in both directions. I guess it is actually supposed to turn the same way as the engine on the water pump I have, but the fins on the impeller look like a letter "C" and that would mean they push water from the convex side. That is not how I would have built one, I would have made the fins such that they trap water in the concave side of the "C" and force it up into the engine. But Bob Buick never asked me to help.
The main reason I think it should turn that way is after looking carefully there are areas of the water pump that get more shallow... obvious places for water to travel through the pump and into the engine, and they look like they would be designed for the water pump to turn the same way as the engine. It's the design of the fins that threw me. So I went and spent 10 bucks and got the standard V belt back on there.
Not that it matters, but just to clear up any confusion... the belt I had on there was a double V belt style BB. It comes from Gates that way, like the standard belts except no ridges, just solid. I didn't just use the back of a V belt.

Also while I had the water pump off I used the garden hose with the adjustable jet sprayer to spray up in the engine and into each bolt hole. Nothing too telling happened, no obvious mucky crud running out or anything. But couldn't hurt.

Of interest, when I removed the long bolt that was down low on the passenger side, a flow of water came pouring out. It appears this bolt travels through the water jacket on the passenger side. This was not true for the long bolt found near the middle of the water pump (the one just left of midline). Water did pour out of the 2 other bolts mentioned in the old post I copied and pasted. The long bolt furthest rightward on the driver's side and the long bolt directly under it and to the left. Hopefully I can seal any small leak that may be going on there.

I also put in a new thermostat just for grins.

Another thing I found... that little pipe on the water outlet is awfully small in diameter and mine had some plyable but dried gasket maker that plugged up nearly the whole thing! Quick fix... take that little hose off that runs from the water pump up to the water outlet and stick a sharp ended long screwdriver through there and make sure there isn't crud in there. It's just about perfect size to poke a medium flat head screwdriver through. This time I did that while the gasket maker was still wet. Should help some I hope.

The head gasket sealer is cooling. We'll see if that does anything. Big day tomorrow night... test run following coolant flush, water pump redo, thermostat redo, V belt redo, and head gasket sealer.

The most weird thing is I have had 2 different radiators, 2 different types of fans, tried running it with no thermostat in it at all and the symptoms have basically not changed at all. It's enough to make ya crazy!

[GeeAea]

You don't need anything fancy to valve off the heater hose. Just stuff something in it and put it back on. I bet your problem goes away. If it's not a HG problem, the whole thing points to not enough flow across the rad at higher engine speeds.

[NIX]

Originally Posted by Jim_Lou

You sure seem to have given the cooling system the full monty. The only thing I can think of is a leak from the combustion chamber into the cooling system - either a cracked head or a blown head gasket. And yes, the heat riser butterfly should be open as soon as the engine is warmed up.

And with that in mind: Just have a CO sniffer at some shop above the opened radiator cap. If there's CO detected, you have a blown headgasket. If you don't find anything, a compression test may be necessary, because sometimes gaskets can get leak between cilinders. Though I wonder if such leaks cause overheating problems.

The heater rad is in fact a little rad and when air flows through, it acts as a radiator. if it is not used and all airvalves are closed, I see no harm in bypassing it. It may affect the cooling a bit if it sits in some airflow now, but not so much it should create an overheating problem, or make yours incurable. But maybe some over here may think otherwise.

One thing: are you sure your temp gauge is OK? when it says 230, do you really think the engine is overheating, like smelling burnt? Your oil is still Ok, you said. Synth can handle high temps, but I would think overheating would even affect synth oils.

[LEVE]

Though I wonder if such leaks cause overheating problems.

If the leak is causing loss of fluid by:

• Consumption, passing fluid through combution chamber,
• Overpressurizing the system causing the raditor cap to lift, or
  • Resivour bottle to overflow

Then yes, it can overheat. Otherwise... no, it should not overheat.

Have you check the exhaust for restrictions yet, or did I miss something?

[GeeAea]

The heater rad is in fact a little rad and when air flows through, it acts as a radiator. if it is not used and all airvalves are closed, I see no harm in bypassing it. It may affect the cooling a bit if it sits in some airflow now, but not so much it should create an overheating problem, or make yours incurable. But maybe some over here may think otherwise.

I'm not sure what year this engine is, but every one that I checked on RockAuto had a separate listing for a bypass hose and heater hose. Every engine that I've ever seen that has a dedicated bypass hose has a valve on the heater circuit. That is, it's doing its job of heat exchanging if it's flowing coolant. As it is, he's got two bypass hoses bypassing the radiator. This may not make much difference at low flow situtions if the pump is of sufficient output ..but MAY come into play ...just like the OEM factored when they built the thing, at higher output levels.

..but ..by all means continue with the diagnostic process in determinning the integrity of the HG.

[east116]

Any update? Did you fix the problem? I am having the same problem with my SBC 350, and it is driving me crazy trying to find a solution. If you founf out what was causing your problem, please let me know. Thanks.

[kirk211]

Well !
Today was another let down.
Here's what I did:
1) Set the timing again
2) Filled the radiator again with distilled water and antifreeze at 50/50
3) Checked again for any leaks anywhere
4) Crossed my fingers

On the freeway it got up to 235 again, just like it always does and I pulled off. Just a steady climb. It still did fine in the neighborhood.
Since I ran the block sealer it seems to be doing better, that odd occurrence of jumping up 20 degrees every time I stop isn't happening anymore and it seems to take longer for it to heat up. Guess it may be the head gaskets.

Still no solution. This is so frustrating.