455 overheating, help!!

[gibbo69olds]

Well I need some help folks, I am at my wits end. I have a 69 cutlass with a 455 and cannot solve an overheating issue. I have an aluminum radiator with dual fans and I have had both a mechanical and electrical water pump on it and it keeps overheating, after about 30-45 min sitting in the driveway. I have a 192 thermostat and the fans kick on at 190. Why won’t this engine maintaine engine temp?

[quick86silver]

Its a flow issue regardless of air or water or a heat transfer issue with the contacting surfaces.

Sounds simple but sitting in the driveway will not allow airflow through the radiator and block.

How many cores is the radiator? 3 Core won't do it even if it is aluminum I have learned.
Are you using a fan shroud with those fans?

What is the flow rate of the water pump? High flow water pumps can sometimes not allow enough contact time in the radiator for the fluid to cool, I have had this problem at high speeds. Running without a thermostat can cause this too.

Has the engine been rebuilt causing a tolerance issue?
Were the water jackets cleaned when the motor was rebuilt, sometimes corrosive buildup can hamper cooling.

[Lady72nRob71]

What temp are you seeing? Gauge functioning correctly?
IR thermometers are great for verifying this.

How much air are those electrics moving? I have heard of many of the electrics not having ample airflow for high CID engines.
When standing at the left fender with the hood open, look at the fans. There should be a hot enough blast to make you squint your eyes and make your hair blow. This is what a belt driven fan does when the clutch is fully engaged.

When was the last time the block was flushed WITH BOTH block plugs pulled? A lot of crap can settle to the bottom of the block.

The stock water pump should be able to maintain 192. Simply cutting power to the electric may then just cause a restriction.

Is your radiator fairly new? If not, pulling it and reverse flushing it may help clean it out.

Is the timing set right? Vac. advance working right? Fuel mixture not too lean?

Just some ideas...

[Texascarnut]

Every time an aluminum core radiator is involved there is every likelihood of loss of cooling capacity from internal corrosion of the tubes. If tap water has ever been introduced into the radiator, that point was the beginning of the end for the radiator. Just like a battery nothing other but distilled water should ever be placed into an aluminum core radiator. 50/50 coolant premix contains distilled water (at least it is supposed to).

I'd check the radiator's present capacity verses what capacity is supposed to be. Even a quart difference is sufficient to present overheating problems with some engines at less than highway speeds.

[gibbo69olds]

Responce to quick86silver.

1) The fans should allow plenty of flow to keep the motor cool in the driveway, no? They are advertised to pull 2210 cfm. The elctric pump should flow 35-37 gal/minute and the standard one should be factory flow.

2) radiator , not 100% sure but I will check the part number and info tonight and get back to you.

3) yes the dual fan setup cam with an aluminum shroud.

4) no I have a t-stat, its 192.

5) the engine has not been rebuilt.

[gibbo69olds]

Response to Lady,

1) I shut it down at 240 last night but it has gotten up to 250 and boiling over. The gauge works properly, the fans are suppose to come on at 190 and as soon as the gauge hits 190 they come on.

2) See above response for fan flow, it is advertised. Good test, left fender meaning drivers? My original one did not have a clutch.

3) My guess, never. I have never done it. Block plugs? You mean freeze plugs? How would I pull those?

4) I am confused on what you are trying to tell me here "The stock water pump should be able to maintain 192. Simply cutting power to the electric may then just cause a restriction."

5) Yeah, at the most the rad is a year old. With changing everything 100 times I have yet to see any signs of crap coming out of the cooling system.

6) Timing that is a good questions. It was set this last time when I changed the cam but the timing plate has three marks. I guessed and used the middle one (I think), So let me ask you, did I time it right? The vacum was off when I timed it, that is correct? I am going to check compression on each cylinder and vacum some time this week.

7) Vacum advance, how do I check to see if this is working correctly?

8) How do I check fuel mixture without a gauge?

I appreciate any and all ideas, keep them coming it will give me plenty to check.

Thanks Guys!!

[gibbo69olds]

Texas, good check. I didn't think running the mixture could cause that. Do they tell you that in the instructions? I will check it. Would it rust that quick, less than a year old.

[gibbo69olds]

Dual Row Radiator from Summit. How does that translate to # of cores? I can count them by looking in the cap too, can't I?

[Lady72nRob71]

1) I shut it down at 240 last night but it has gotten up to 250 and boiling over. The gauge works properly, the fans are suppose to come on at 190 and as soon as the gauge hits 190 they come on.

Gauges look good...

2) See above response for fan flow, it is advertised. Good test, left fender meaning drivers? My original one did not have a clutch.

Yep, drivers fender, hood up. The stock rigid mount fan should have had a similar output. Any debris between condenser and radiator (assi=uming you have A/C?

3) My guess, never. I have never done it. Block plugs? You mean freeze plugs? How would I pull those?

Nope, Two 9/16 inch hex drain plugs - just unscrew 'em. At the front of the block, above the oil pan, one on each side. If the engine is dirty, they should be under a bunch of muck (like my 350's were)... I assume the 69 455 would have similar plugs???

4) I am confused on what you are trying to tell me here "The stock water pump should be able to maintain 192. Simply cutting power to the electric may then just cause a restriction."

Sorry, I seemed to have deleted a line or two that stated, try to bypass the electric pump to make sure the flow is not TOO fast. Cut power to the electric and totally bypass the pump with a hose coupler.

5) Yeah, at the most the rad is a year old. With changing everything 100 times I have yet to see any signs of crap coming out of the cooling system.

Simple flushing will not remove most hard water deposits or corrosion.
Try just water & 2 bottles of the prestone super cleaner, run for 8 hours, then drain, backflush with water. Back flush radiator with a hose and the block, too, with the block drains open... I saw a big difference in my rad by doing this.

6) Timing that is a good questions. It was set this last time when I changed the cam but the timing plate has three marks. I guessed and used the middle one (I think), So let me ask you, did I time it right? The vacum was off when I timed it, that is correct? I am going to check compression on each cylinder and vacum some time this week.

Vacuum hose disconnected and plugged - correct. set timing per vehicle spec. (I do not know off hand what the 69 455 needs. The middle mark on the 72 is 6*BTDC.) Check into this.
----Did the overheating start just after you changed the cam??

7) Vacum advance, how do I check to see if this is working correctly?

Disconnect vac hose from disty and plug hose. Run long clean hose to disty vac advance can. Start engine. Idle should be lumpy. Suck on hose. If RPM changes, it should be doing something. Suck on hose with timing light on pointer - mark should appear to move (poor man's quick test).

8) How do I check fuel mixture without a gauge?

Not sure if a gauge exists for this... Pull a spark plug or two and observe the color. Blistered white or grey insulator by tip indicate too lean. It should have a light coffee brown color to it. Black soot is too rich. Oily is oil leakage.

[Texascarnut]

Originally Posted by gibbo69olds

Texas, good check. I didn't think running the mixture could cause that. Do they tell you that in the instructions? I will check it. Would it rust that quick, less than a year old.

I'm not sure I understand this statement. But just to be safe, a 50/50 premix of Distilled Water and anti-freeze is what is recommended for an aluminum radiator, unless the manufacturer of the automobile it came in or the manufacturer of the radiator recommends something else. Yes, there would have been an advisory of some sort regarding the type of coolant fill whether in an owners manual for the car, the box a radiator is shipped in, or a data sheet inside the box.

To make things clear; tap water, whether from a city water supply or a well, will have varying degrees of chlorides (salts) and other chemicals which are not friendly to aluminum in it. All chlorides are potentially the enemy of aluminum.

[joe_padavano]

I have to say that I've never had an overheating problem with BBO in any state of tune. There's clearly something wrong. It could be blockage in the cooling jacket, it could be a very small head gasket leak, whatever, but your combo should not do this even when sitting in the driveway.

I also caution everyone that the number of rows in a radiator is not an important metric. It's the total surface area of the tubes that matters. Many aftermarket aluminum radiators use tubes up to an inch wide. My 86 with 307 has a single row aluminum radiator and it runs cooler than the OEM three row copper unit. Most big block aluminum radiators use two rows of the wide tubes and they cool just fine. The issue with either corrosion in the radiator or crud that's worked loose from the block and is plugging the radiator is a good point and should be checked.

[88 coupe]

Start with the basics:

Originally Posted by gibbo69olds

........ it keeps overheating, after about 30-45 min sitting in the driveway ........

Does it go over 195° at highway speeds? If it doesn't, the fan is not moving enough air (at idle) to do the job. If it does, the coolant is not moving as it should.

Originally Posted by joe_padavano

I have to say that I've never had an overheating problem with BBO in any state of tune ........

Retarded spark can cause higher than normal temps, but most of us would notice the decrease in power, and correct it before it became an issue.

Norm

[gibbo69olds]

Lady

2) No AC
3) I will look. Any know if these are on a 69 455?
4) Right now the stock pump is in the car.
5) you think the rad could be that blocked up in only a year?
6) No, I have always had a cooling issue.
7) I will check it.
8) I will check the plugs and report back on everything probably after the weekend.

Texas, You addressed exactly what I was asking about the rad, thank you.

Joe, I changed the head gaskets less than 8 months ago with the mondello $120 gaskets, there better not be a leak.

Coupe, It overheats in all circumstances. The car has really good power but I will check and double check everything just to figure this out and report back.

Thanks again guys, I will let you know.

Steve

[joe_padavano]

Originally Posted by gibbo69olds

Joe, I changed the head gaskets less than 8 months ago with the mondello $120 gaskets, there better not be a leak.

Sound like there is at least a leak in your wallet...

It might not be a bad idea to run a quick leakdown test. This should allow you to determine how well the cylinders are sealing and if there is a leak, listening for the escaping air at various locations (radiator, oil fill, exhaust, etc) will tell you where it is.

Run the engine until hot then shut it down and feel the face of the radiator core. If it is plugged, you will feel a distinct difference in temperature from the plugged to open portions. I had this problem with a big block truck once and the difference in temp on the face of the radiator was very easy to tell.

Have you actually put the t-stat in a pan of boiling water to verify that it opens fully?

[gibbo69olds]

Joe, I wish I did but I really just want to fix this thing so I can drive my car. I have spent hundreds of dollars on it and am completely feed up. I have not checked this tstat. It is brand new and I will, I check the 160 I had in it originally and it opened properly.

Please check back on Monday guys so I can give you all new data and you can help me further if I have not gotten it.

I really appreciate everything!!

[FATRATMATT]

I have a friend who has a big block Chevy and he had the same problem with it over heating. It was a rebuild motor, new radiator, water pump,thermostat, dual fans, ect ect ect. He chased this problem for a few weeks. I seen him at the weekly car show and he told me something that made me look at him like he was nuts. He said " I put on a new carburator" He has not had a over heating issue since. I guess the fuel mixture was too lean and it caused a over heating problem. Sounds funny but thats the truth. Its worth a look.

[Texascarnut]

Originally Posted by FATRATMATT

I have a friend who has a big block Chevy and he had the same problem with it over heating. It was a rebuild motor, new radiator, water pump,thermostat, dual fans, ect ect ect. He chased this problem for a few weeks. I seen him at the weekly car show and he told me something that made me look at him like he was nuts. He said " I put on a new carburator" He has not had a over heating issue since. I guess the fuel mixture was too lean and it caused a over heating problem. Sounds funny but thats the truth. Its worth a look.

It may sound nuts to some, but I have also known of a couple of guys with big blocks (not Olds) having the same problem. In both of those cases it was because they had been talked into putting too much carb on the engine.

[88 coupe]

Originally Posted by FATRATMATT

........ the fuel mixture was too lean and it caused a over heating problem ........

I don't think your "friend" told you the complete story.

Originally Posted by Texascarnut

........ (not Olds) ........

One that is not subject to the same laws of physics?

Originally Posted by Texascarnut

........ because they had been talked into putting too much carb on the engine.

I don't think your "friends" told you the complete story.

Norm

[z11375ss]

Collapsed hose perhaps?

[gibbo69olds]

OK, here are some things I found and additional questions that I have. I have put three pics here. One is my timing plate, could someone please tell me what each mark is? Then there are two pics of representative plugs. In your opinions do you believe that they look normal?

I tried the disconnecting the vacuum advance and I did not see a noticeable difference when sucking on it. It did get lumpy when it was disconnected but how much change should I hear when i am sucking on it?

I ran the fan and put my head pretty much in the engine compartment on the drivers side and I would say that I felt a light breeze when they were running.

I am going to check more things tonight and report back asap.

[Oldsguy]

On the timing plate; the lower notch is zero reference (the "0" in the metal). The second notch up from there is 10 degrees advance (the "10" in the metal).

I usually use AC Delco plugs so can't be sure about those you have but they sure look long, are you sure they are the correct ones for the 455? As far as how they look, they look pretty normal to me. They sure don't look like they came from an engine that has been running hot (at least for a period of time anyway).

[kaz442]

Is this this a rebuild? If so what is the piston to wall clearance? Just a thought. JKaz

[gibbo69olds]

ok so my next question is what should the timing be for this motor and does it matter what car it came out of?

The motor is not a rebuild.

Back to the vacuum issue, still no change when sucking on the vacuum hose. I checked the vacuum when cranking and the needle bounces from 3-5 but not steady. at idle running I had 7 reved up I have 20. Now when I tap into the vacuum advance I get 13.5 at idle, when I throttle up it drops to about ten then right up to 20. When I let off the throttle it jumps to 25 and then right down to 15. Does this all sound normal.

I do not have drain plugs in my block like described above by lady.

So anyone have any other tips / items to check.

[gibbo69olds]

Oh yeah, radiator seems to have the same temp to the touch across the entire surface area.

[gearheads78]

Pressure check your cooling system both cold and hot. This will eleminate if there is a small internal coolant leak.

Won't cause overheating but ditch the Bosch plugs. Last time