Cursed overheating..

[defiance]

Ok...  After seeing the nastiness that lies beneath my vynil top, I'm just about ready to give up on this accursed thing...  But not quite.  I still have 3 things to fix, the steering (just need to replace the steering box, no biggie), the vynil top, and whatever the hades is causing my incessant overheating.  I keep thinking I've fixed it, but then I run a good test and no, it's still there.

So here's where I am right now.

The car has a relatively new water pump (less than 1k miles), new radiator hoses, BOTH with good springs, new 19" * 26" 2-core aluminum radiator, two 12" 1360CFM Spal 'pusher' fans in front of the condenser and another pair behind the radiator in a custom-made shroud, seperate tranny cooler with dedicated 9" spal fan, all MSD ignition (distirbutor, 6 box, coil, and wires), air/fuel ratio slightly rich (12.5/1) at idle, new 180* thermostat, new 16psi rad cap, timing configured to 15* advance at idle, 36* max at 3k rpm...  I've replaced just about everything in my quest to fix this issue, and nothing works.  I have thought I had it fixed a couple of times, but no such luck.

My goal is to simply get it to idle at a constant temp of around 180*.  I figure it should darn well be possible with this configuration (VERY mild 440), and if it can do that, I can drive it without worrying at all.  As of now, configured as above, it takes around 12 minutes to reach 180*.  After this, it passes 200* and rising in less than 8 minutes (so it slows down when the thermostat opens, but it doesn't stop).

I have tried removing the thermostat, it made a difference, but ONLY in warmup time.  The fans don't kick on 'til 170, so it made it there in right at 20 minutes, but took another 5 to hit 180.  Once again, though, in 10 more minutes it hit 200 and still rising.

I tried adding in more advance (up to 25* initial), playing with different thermostats (180, 160, restrictors, etc), playing with water/antifreeze mixture, nothing helps.

I haven't seen any bubbling in the radiator, so I don't think it's the head gasket, but I haven't actually looked for it specifically.  I'll look tomorrow...

Does anyone have other ideas for what it could be?  If I didin't shave my head, I'd have pulled it all out by now......

[myk]

My 440 runs at 180 for the most part.  In traffic, 200 to 220 is where my motor ultimately remains.  Honestly, I don't think there's anything wrong with your system at all.  Other members here will tell you that your temperatures are normal...

[Ghoste]

Idling with an automatic and a two core rad, 180 may be as good as it gets.   Have you hit it with a laser temperature finder to verify what the guage is telling you?
Some that Water Wetter stuff may bring it down a little as well.

[defiance]

Well, it's not as bad as it gets, though...  Like I said before, when I stop it, it's at 200 and still rising.  Driving the car about 30-40 minutes the other day, by the time I got home it was nearly 240...  I don't want to drive it again until it's fixed...  But I just have no idea what to do to fix it.    I've got two gauges in the car as well; one for the ECU, and one for the dash.  The ECU uses a GM sending unit, so it's about as different as it gets, but the two are in agreement, so it should be pretty accurate.
As for the two-row radiator... I've not seen anything more than two rows in aluminum...  All the Ron Davis stuff I've looked at is two-row...

I plan to check for bubbling this evening.  I'll let it run longer and see how long it takes to get to 220.

[TylerCharger69]

Well...I'd try   going to a 3-row  instead of a 2  on the radiator.....Also...are you running a shroud??   That's makes a big difference

[firefighter3931]

You might have an air pocket in the cooling system. Get the front of the car up on ramps and run the engine with the rad cap off and keep an eye on the coolant...if there is a pocket the rad will burp and the coolant level will drop once the air is bled out of the system. I suggested this for another member who was having overheating issues and it worked.


Ron

[resq302]

You might have an air pocket in the cooling system. Get the front of the car up on ramps and run the engine with the rad cap off and keep an eye on the coolant...if there is a pocket the rad will burp and the coolant level will drop once the air is bled out of the system. I suggested this for another member who was having overheating issues and it worked.


Ron

Yup, Ron helped me with the above issue.  That burp trick did it for me.  Just out of curiosity, did you have this problem prior to draining the cooling system?  If so, you probably have to raise the front end and burp the baby.

[grouseman]

It's gotta be the radiator.  You've got coolant flow and air flow, the only thing lacking is the radiator's ability to transfer the heat fast enough.  Does your rad area take up all the space available in the opening in the rad support?  And 3-core will also help. 

[defiance]

Who makes a 3-core aluminum?  Be Cool, Ron Davis, etc., all the aluminum radiators I've found are 2-core...?

Anyway I'll try burping this afternoon ...
er, wait, no, it'll be tomorrow afternoon, forgot I had class tonight (doh!).  I'll put it up on stands (don't have ramps) and see if I can get be sure there are no air pockets.  I'll also check for bubbling.

I don't know, though - this is a brand new aluminum radiator, and the old (actually only about 6 years old) stock copper 3-core, 26x19 radiator had the same issue, so I'm really thinking there must be something else wrong (I'm definitely willing to consider the radiator as a possibility, I just want to understand why...)

The radiator does cover the whole area.

[defiance]

Ok - Lifted it as high as I could on the stands, started it, no 'major' bubbles.  I let it run up to about 220 with the rad cap off.  Took around 30 minutes.  Throughout the process, there were occasional tiny bubbles, but by occasional I mean like a tiny bubble every 2-3 seconds.  To me this doesn't seem like a head gasket issue, but at this point *EVERYTHING* I know of has been done; I almost wish the head gasket was done for... at least then I'd have an answer. 
Having said that, is there any chance the had gasket could be blown, causing heat, without causing any coolant bubbling?? 

Otherwise, I'm COMPLETELY out of ideas

[firefighter3931]

I think it's time to pressure test the cooling system. You should be able to rent or borrow a tester and figure out if it's losing pressure somewhere. Does the oil look discolored at all ? How about the coolant....any discoloration ?

Have you taken it out on the hwy to see if it will cool down at cruising speed ? If it runs cool on the hwy then the problem is related to airflow. If it doesn't then the problem is most likely the radiator.

The other thing i'm wondering about is all those fans you've got going. Pusher and puller fans together.....i haven't seen that used before. My buddy runs a pair of pullers on his 600hp 472 hemi and it doesn't hit 200 *  Another friend has a puller on a blown 440 and it stays cool as well (under 200*). Both are using a 26x19 (2 core) alum rad just like yours.



Ron

[TylerCharger69]

just a shot in the dark here....but.....how much oversize has the cylinders been bored??

[defiance]

I'll see about pressure testing the system, but when it gets hot, flipping the lever on the rad cap (16psi stant) results in a high pressure discharge from the overflow tube, and it doesn't seem to leak otherwise...  That's probably not a definitive test, but it doesn't *seem* to have any leaks...

On the interstate @ 60mph, it got over 240 halfway home from Benton, so highway driving didn't help... 

I can't see pusher-puller combo making things worse, but I can easily disconnect the front two and see ...

As for the bore... ... ... Now you're worrying me
I checked with my dad (he had the engine built a while back), and he didn't remember but he "thinks it's around .40 over".  Now, I don't know this as a fact, but 440 pistons are available in .030 or .060, right?  I've never heard of .040... 
Another freaking wild card.  This car is REALLY pissing me off 

If it's .060 and the block wasn't ready for that, can overheating be a result?

Dammit.  I'm going to have to tear this engine down...  and I know diddly about engine internals...
*sigh*

[Ghoste]

Has the cooling system ever been flushed?

[TylerCharger69]

WOW....240 degrees is BAD!!!  That is high!!!   I've heard some stories of a .060 over engine having overheating issues...and then on the other hand i've heard that there were no problems.  But more so problems than not.   Another alternative to check may be.....is your water pump sound?   How many impeller blades does it have?  Is it a remanufactured piece?......I'd exhaust all of your options before attacking the overbore hypothesis, but that may be an issue....

[Chryco Psycho]

.040 over pistons are available for 440 , so are .055 over & virtually any oversize you want to have made
I have to agree though borrow a pressure tester & see what happens , steady bubbles are generally a bad sign 

[defiance]

The water pump is fairly new; the engine hasn't run more than 10-15 hours since last time it was first installed.  I don't remember how many impellers...  I think 8, and they were somewhat fan-shaped.

The system hasn't been flushed...  Since everything is so new, it hadn't occured to me, but the block isn't new, so that could be a problem.  I'll try that.

I had dad stop by the shop that did the work and ask, the guy said he was 'almost certain' it was .030 over, and that it had been sonic checked, so that's probably not a problem.  If I can't resolve it without tearing the engine down, then I'll check the pistons and see, but for the moment I'm going to guess that's not it... hopefully...

Oh, as for the 'steady stream of bubbles', like I said, I'd love to have seen a good stream, since then at least I'd *know* the problem is the head gasket.  But does a tiny bubble every few seconds really count?

Ok - so this evening I'll do the following...

1- Cooling system flush ...  I'll just disconnect the radiator, remove the thermostat, pour in some sort of cooling system flush stuff (I'll stop by advance after work and see what I can find for that), then pump water through until it comes out clean.  Is that a good procedure?  Or do coolant system flushes require the engine be warmed with the flush in them?  Eh, whatever's on the instructions, I'll do.  As noted, the radiator itself is new, so I don't think it should need to be flushed, but I'll do it anyway to be sure.

2- *edit* - actually, Auto Zone has coolant pressure testers as loaners, so I'll just go that route, and I'll test that tonight as well.

3- re-run the whole battery of tests


Any other suggestions or anything I missed in the post?  Trying to check everything mentioned, but there's a LOT of stuff up there (Thanks for all the suggestions by the way... I came here stumped and now at least I have more to check!)

[resq302]

After you burped the cooling system and got those tiny bubbles out, and replaced the rad cap.  Did it help the cooling system run cooler or no?  Do you have a fan shroud?  Do you have a fan clutch?  A bad fan clutch could cause overheating issues too I have heard.

When I burped my cooling system, I also had a bunch of tiny bubbles coming up which was slow but then eventually they all disappeared.  If you are consistantly getting tiny air bubbles, then I would say you have a bad head gasket.  Also, try pulling your plugs to see if there is any discoloration on the plugs.  That could also indicate a bad head gasket.

[defiance]

Nah, didn't help...  Still went over 200 pretty quickly.  The bubles were still coming when I put the cap on, but *VERY* slowly; I'm not 100% sure they were actually coming out of the radiator- could have just been from the moving water in the open cap area vibrating a bit and making an occasional bubble...  They were that small and far between...  Plus, I can't let it run for more than about 30 minutes, now, so maybe even if the bubbles are  So before I pull my heads I want to try to find more confirmation that it's really the head gasket!

The fans are all electric, two 12" spals pulling behind the radiator in a full coverage shround, then two open in front pushing.

I'll pull the plugs tonight to look for discoloration and pressure check the cyllinders while I'm at it. 

The more I look at it, the more I'm pretty sure it's the head gasket, though...  I just remembered something critical.  The radiator starts burping a bit of water at around 210-220 degrees, with a new 16psi stant cap.  I never really thought anything of it; that's hotter than I ever want it to run anyway...  But now I came across some indicators saying that it should never overflow until at least 230-240.  If that's the case, wouldn't that indicate some excess pressure entering the system (i.e., head gasket)?

Looks like I might have my 'wish'...   Not good, but I guess it's better than not knowing.

[sext7366]

about a year ago my 383 was starting to blow a head gasket.  By starting I mean that it idled and ran fine besides running about 230 degrees.  The only indication was a very minute amount of smoke from the passenger rear head that would puff every three or four seconds from the water slightly coming out of the gasket.  It ran fine though.  So this may very well be the problem.  i just recently went with a two core radiator 180 degree thermostat trans cooler and thermal fan clutch.  I still do not have the shroud put on and my 383 is bored .060 over ....long story short on the highway my setup dropped from an average 215 degrees to 195 in the hot Oklahoma summer over 100 degrees outside.  Check the gasket if all else fails.

[defiance]

Thanks....

I think I've pretty much accepted the idea of replacing the head gaskets and all that goes with it now.  .. .. I figure it's a good time to answer some of the 'questions' about my engine anyway.

So with that said...  I've changed the head gaskets in my old '92 buick (5.7l, probably the same as a chevy 350?), but I didn't really give a flip, so I just grabbed whatever Auto Zone had cheap and did only the minimum amount of work possible.

For this car, I want to do it right...  But I don't really know much about gaskets...

So, I'm going to list what I *think* I need to get and do, and if anyone sees anything I need to change, PLEASE let me know!!

First, the parts I think I'll need:

--Head bolts - Summit shows a set of ARPs for $54, or a nearly identical set for $77, only with a "special moly assembly lubricant" - I'm guessing that's probably not worth $23...?

--Gaskets - Summit again, fel-pro kit for $56.39 (full engine gasket kit, FEL-KS2110)

--Copper spray gasket sealer stuff (can't remember the name); I've heard this is preferred for sealing head gaskets...?

--high-temp RTV for less critical gaskets (thermostat, water pump, valve covers, etc)

--The tab on my timing chain cover blocks my view of the timing marks that are etched into my harmonic balancer, so I think I'll replace it with one with a smaller tab while I've got it all open

--I'm going to need a harmonic balancer puller/installer - I had one once, but the threads on it are all jacked...

--Cylinder and radiator pressure testers - I already plan on getting these anyway...



Next, the process:

-drain oil, drain water, drain p/s fluid

-remove radiator/fans (mostly to get room to work)

-strip off all the accessories.  Fold the a/c compressor out of the way instead of removing if possible, don't want to re-vac / re-charge / replace dryer / etc.

-Remove air cleaner setup and all above-engine wiring

-remove valve covers

-remove rocker arms and pushrods, marking which go where

-remove intake manifold/throttle body (don't see any reason to seperate these...?)

-unbolt exhaust manifold

-remove head bolts

-remove heads

*this is the part where I lose confidence in my understanding...*

*this is a bit of an extra step I'm taking so I actually KNOW what's in this engine.

-remove timing chain cover, timing chain, and cam - hopefully there will be some sort of identifying marks on the cam??

- also, note markings on the piston for use determining overbore amount and compression

-Back to the primary goal, my dad tells me that the heads need to go to a machine shop for checking (dynaflux? he called it).  Ok, any guesses on how much that's going to cost?

-Install head gaskets by coating one side with sealant, putting them on the block, coating the other side, then putting the head in place on top of them.

-Torque bolts in a specific order, to a specific spec (I've got one of those cheap auto zone repair manuals - pretty useless generally, but it has this in it at least )

-Re-bolt exhaust manifold with new manifold gasket - my understanding is that no sealant will be used here???

-Re-install intake manifold.  What sealant should be used here, RTV, or the same copper stuff that is used on the head gasket?

-From there, just re-install all the parts in reverse, using gaskets and RTV as needed.




Is that a pretty accurate description of the process?  If so, anyone have any ideas what the cost of the dynafluxing is going to ballpark?  I'm completely clueless on that part...

Thanks!!!

[Chryco Psycho]

sounds about right , you can use the Mopar steel shim gaskets for less than 1/2 the price & coat them with copper coat  this will increase compression slightly
if you use the FelPro head gaskets Do NOT use the sealer on them
you may want to have the heads milled .004 to make Sure they are flat
the heads can be maganfluxed for cracks not sure on the cost or dye glowed
exhaust manifolds were Never used from the factory , I use a thin layer of high temp silicone & bolt them onto the head , if you WANT a leak I recommend using a gasket they always leak soon after installation
You do not need new head bolts but they can`t hurt if you want to replace them
usually cam markings are on the rear of the cam requiring you to remove it from  the engine , no need to pull the timing cover & damper unless you need a chain or want to identify the cam
just use silicone in the corners of the intake gasket to stop oil leaks , you can use a 1214 or 1215 [RB] to block the heat crossover under the carb while the engine is a part 

[1970440RT]

    Before you rip the motor apart, try this: 

    Remove the shroud and all 4 electric fans.  Take a large blower fan ( the type used to push large amounts of air, similar to the ones that inflate the big " moonwalk" kids toys you can rent ).  Set this fan up in front of the car and let it idle.  If this does not keep it cool, then you know for certain that the cooling system for whatever reason is not up to snuff.  This is a cheap and simple test that may save you from doing a ton of work for nothing. 

     A 26" 2 core aluminum radiator should be more than enough to cool that motor.  If you have the square shroud with dual fans, which I think you do, it is killing your airflow through the radiator at cruising speed and once the temp goes up over 210, the electric fans can't move enough air to bring the temp down.  I had the square shroud on my radiator and would see 210 to 220 on the highway depending on vehicle speed.  I removed the shroud and took the car out on the highway to test and the temps went to 180 to 190.  Problem solved. 

     Personally, I will go back to a thermo. clutch fan and stock style shroud because it moves the most air at idle.     

     

[defiance]

Actually, at this point, with all the cooling configs I've tried (good-condition 3-core stock + flex fan + shroud, change that for flex fan, change that for three electric 12"-pullers without shroud, add two 12"-pushers to the front, change 3 fans to 2 with shroud, drop the entire radiator & replace with alum, and when it was on the dyno, a big blower fan like you talked about was used..... Always with the same problem.  I really think there's no way this could be the cooling system.  So, with the dismal performance of this motor (212 rwhp/357 tq) plus this stupid overheating crap, I've decided to tear down the engine top half and rebuild from there.  Got another post going asking for advice on configuration... 

Thanks for all the recommendations, in any case!

[grouseman]

We all share your frustration, man, we've all been there to some degree.  Maybe not as bad as your case, but we're all in there pulling for ya. 

Confirmation from the experts - will a 'slightly' blown head gasket leak into the cooling passages result in such overheating without blowing the rad cap off? 

FWIW, a friend has a '68 Firebird.  He was going through the same overheating issues as you were.  He tried everything - rad, stat, hoses, fans, shrouds, etc.  What it turned out to be was related to the Pontiac style of water pump.  There is a stamped steel plate which must be clearanced correctly next to the impellers in order to develop flow; otherwise all the pump does is churn water in the housing.  Once that was fixed, the engine stayed rock-steady at the 160 mark with a 160 stat.  It was then too cool, and moved up to a 180 stat.  I don't know big block Dodge water pumps and housings intimately, but is it possible that the impeller is somehow the wrong one?  It is easier and cheaper to change the water pump than overhaul an entire engine, so it's maybe worth the check.  Good luck.