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

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:

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.

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

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

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

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

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

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 I had luck with them I was working on air cooled VWs

gibbo69olds

really, i use bosch plugs in everything and have never had any issues. i usually get better gas mileage. What do you recommend? i did pressure check my coolant system a while ago and everything checked out ok. i will do it again though.

64Rocket

I would bring #1 cyl. up on TDC and see where the timing mark is at compard to the timing pointer. your balencer may have slip.
I would lean more toward a water pump. I have seen the stamp steel impeller break off. Also some of the stamp steel impellers are to small, like only 3" in diamater. I always get the water pump with the cast impeller that fills all out to the edges of the pump housing.
The problem you have is a flow problem.

Geno....

Lady72nRob71

Glad the site is back up!!

>>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 never tried this on an Olds, but on my old Ford, I could change the lumpy idle back to smooth when sucking on the hose. You plugged the connection where you disconnected the disty hose, right? Otherwise you would just introduce a big vac leak.
Is the the vacuum can on the disty is HOLDING vacuum? after a few small sucks, you should not be able to suck any more. If you keep sucking air, there is a leak.

The spark plugs look about the right color, but of a different type...

Your timing plate looks different than mine, so I cannot say much about it. I assume your emission decal underhood is gone, as it is on that.


>>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.

A "light breeze" does not sound like much... Mine put out a light breeze when the fan clutch had failed. I thought that was normal. When i replaced it, it moved a LOT of air. Putting my head in the engine bay was uncomfortable given the stong blast of hot air.
Do you happen to have the stock fan and shroud? I would be tempted to reinstall it to see if the problem gets better.
Anny debris between the condenser and radiator (I had that issue.) Lots of bent fins on radiator (I assume that was checked already...)

64 rocket had a good point too. All water pumps are not created equal. Look at the end of my picture collection in my sig and I have a good and bad pump side by side. One is a cheap 1yr rebuilt and other is new Master lifetime. Impeller blades are different sizes, not only in diameter but also in depth. The one-year also comes with seals that last 1 year 3 months...

Cooling system issues are often multiple problems combined and I had almost all the problems it seemed...

gibbo69olds

Remember guys I have had two different pumps on this, one is the stock and seems to be working ok, the other is the electric one (flows 35-37 gpm) with not much difference. I don't think this is it but are you (lady and 64) suggesting spending money on a better pump. I would hate to do this when I am not 100% sure.

Yup, plugged the vacuum line that I disconnected it from and I can not continue to suck on it but I also do not see a great difference. I should be able to rebuild this or do you think a new distributor would be best.

Remember guys this is a 68 engine in a 69 no emissions and no ac. The engine came out of a delmont 88.

DOES ANYONE KNOW WHAT THE TIMING SHOULD BE ON THIS ENGINE?

I do have the stock fan and shroud but I will not be able to place the shroud back because I modified the rad bracket. I can replace the fan though. I could try this.

I looked at your pics but wouldn't the new electric pump help all this?

I am running out of things to check.

What do you guys think I shoudl start with?

Oldsguy

Most 455s are good at 10 degrees advance. Check out this link, it may help you out.

gibbo69olds

I might be off then. I will check / change it and report back.

Thanks for the link, I will also check compression.

Lady72nRob71

>>Remember guys I have had two different pumps on this, one is the stock and seems to be working ok, the other is the electric one (flows 35-37 gpm) with not much difference.

I forgot about the dual pumps, as the site was down for a while and I slept a lot on the weekend... Yes, if the stock pump was inadequate then the electric should have helped if it was working properly.

8-10 degrees @ no advance looks about right but I do not know how that timing plate should be marked. If you scrape all the rust and / or paint from it the numbers ~might~ be on it like on my 72's.

A timing check should be next to verify proper initial setting and correct vac advance.
Could some kind soul check their 68's 455 emission decal (or tune up decal) for how the timing marks on the plate are marked?

When it starts running hot, does turning on the heater on high cause the temp to drop some? Heater air temp should be 150* or hotter. Less than that and the heater is partially clogged, meaning the block could have a lot of buildup in it also.
Too bad at having no block drains. When you did flush it, did you just run the engine to flush it or did you use a garden hose (with no t-stat, heater unhooked)?
I am running out of ideas, also.

gibbo69olds

The vac advance would not affect anything sitting in the drive, right?

I will try running the heater, but I am almost positive it does blow hot, not sure how it would affect the running temp though.

Lady72nRob71

The timing should be advanced quite a bit while sitting idling in order to run smoothly. Pulling the advance hose should retard it, causing the idle to be rougher. There should be a good noticable difference, anyone agree/disagree? I know it has been a while since I have messed with timing, but I need to exercise that soon and check mine!


When the heater is on and fan is at high speed, it is acting like a second small radiator, transferring engine heat to the air inside the car.

I have heard this is what one should do if the temp gauge heads hot or the idiot light comes on during a trip (usually stop and go in hot weather):
--Shut off the A/C and crank up the heater full blast. If it continues to rise or light does not go out soon, shut the engine off as a major fault has occured.

Lady72nRob71

One question came to mind - Where does your disty advance hose connect to on the engine?? Need to make sure it is at the right port.

Oldsguy

Actually, it UN-advances it back to baseline...

I agree, sort of, if you dis-connect the vacuum advance to the distributor and forget to plug the vacuum leak the engine will run poorly. If you plug the vacuum leak it will just idle a little lower, most of the vacuum advance comes in upon acceleration.

gibbo69olds said minimal effect at idle, however, I think were some people were going with this is, if your initial timing is way too retarded then the engine may be running too hot because of that. That is what 64Rocket was getting at. Has the balancer slipped? look for cracked rubber all around the circumference of the metal inner portion that is bolted onto the crank snout. If it hasn't, then you can set your timing to 8 to 10 degrees advance at idle with the vacuum hose to the distributor advance pot disconnected and the vacuum hose plugged to prevent a leak.

Lady72nRob71

>>Actually, it UN-advances it back to baseline...

I guess this what I had in mind but worded it poorly.


>>I agree, sort of, if you dis-connect the vacuum advance to the distributor and forget to plug the vacuum leak the engine will run poorly

I guess this is what I remembered from way back then. I knew there was an idle change but maybe just before the leak was plugged.

My timing experience is a bit rusty indeed. It's about time someone set me straight ...

(Hopefully I will now remember it all for when I go to check my timing!)

88 coupe

Vacuum advance has nothing to do with your problem.

Read this post again.

Then, read this one.

Something is obstructing your coolant flow.

Norm

88 coupe

Does anyone else see the humor in this one?

Norm

88 coupe

Lower hose will not collapse, at idle. It can be tested, by raising the RPM to 2000, or so, while observing the hose.

Norm