413 Engine Overheating and I Thought I Fixed Everything

[MSN Member]

From: Catalina362 
Sent: 6/26/2007 7:15 PM

I have a 1973 brave with a 413 engine. I took it to Idaho last summer 06 from Los Angeles and had no trouble, except for here and there an electrical problem, until I got back to the highway 58 and Mohave Desert. Here we began experienceing over heating problems and all year since then I have been trying to fix it. Luckily I never let it overheat it just got really hot and I stopped to let it cool down. I have replaced the water pump, reconditioned the radiator at a radiator shop, changed the plugs and wires, flushed the engine several times before redoing the radiator and after the radiator rebuild, Changed the lower hose checked for leaks (finding none), and changed thermastat and gasket with a 160 lb thermostat. I am going to change the fan clutch but up till now it still gets very hot on hills 1/4 the size of the Grapevine hill roughly 1-3 miles of up hill driving. Is there anything I am missing? When I change the fan clutch I will add the results to this list. If anyone can help with any advice to fix my heating problem I could really use it. The motorhome had not had any trouble overheating until last summer in mohave, and since then I haven't been able to find the trouble.

[Lefty]

Sent: 6/26/2007 7:31 PM

Overheating can be due to a number of factors. Some that you could check are;
Ignition timing
Mechanical advance not working properly
EGR valve not closing, causing a lean mix
Faulty air/fuel ratio (too lean)
Blown or leaking head gaskets
Cracked head
Fan clutch not dis-engaging at hiway speeds  (a locked fan clutch actually restricts the airflow that normally would come in due to a slight ram-air effect at hiway speeds. fan clutches are only engaged at low engine speeds, and low mph's.)
Faulty or defective thermostat (it happens)
Blockage in the water jackets due to a build up of deposits (rare)
Faulty temp sensor making you think it's too hot, when it's not.
Improper mix of antifreeze to water  (should be 70% antifreeze to 30% water for maximum boil over and freeze protection)
Improper or faulty radiator cap not holding required pressure
Missing or damaged overflow bottle  (newer models only)

Not a complete list, I left off the things you said you've already did or checked. But this should get you started.

[MSN Member]

From: Catalina362
Sent: 6/26/2007 7:47 PM

I forgot to mention that I did replace the radiator cap with a 13 lb cap on advice of the Radiator shop. Thank you Im-still-lefty for your check list. I will do what I havent done yet, starting tomorrow, and then I can let you know what else it is doing. Thanks again.

[MSN Member]

From: Boots
Sent: 6/26/2007 8:39 PM

My guess is there is some blocking in the heater core? Only a guess but, in the olden days if the motorcar started to overheat turning on the cab heater would aid in cooling it down.
Boots

[MSN Member]

From: Catalina362
Sent: 6/26/2007 8:53 PM

Thanks boots. The heater core is not conected at the moment. The hose that would go to it is just sent rite back into the block. I haven't gotten it rebuilt yet so there is not help from turning the heater on. Sorry I forgot to mention that. The carborator is a four barrel Holly carb, and the origional owner put headers on it to " inprove gas mileage" it didn't help the mileage but it does have plenty of power. Could this be part of the problem?

[MSN Member]

From: firehart2
Sent: 6/26/2007 9:14 PM

My 73 Brave also has a 413. Someone put dual cherry bombs on it. Its so loud it wakes up all the neighbors. As soon as I get it running better I am going to check out the cooling system. It has only had 40 miles put on it in the last three years and 20 of those I put on driving it home. I'll keep my eye on this thread to see what I have to look for.

[denisondc]

Sent: 6/27/2007 3:06 AM

The headers wouldnt have anything to do with the coolant getting too hot.
Besides the other advice; make sure the bottom radiator hose isnt getting sucked shut by the 'negative' water pressure. Your thermostat should look like the ones you see at www.summitracing.com when you do a product search for MRG-4366 oe MRG-4367. They need to be the 'skirted' type to work best - more important the hotter it is. The OEM fan clutch would have been the vicsous drive kind, probably with a thermostatic element sticking out the front - and they never just quit. They lose their abilityto properly cool little by little. But that shouldnt result in overheating when going over 40 mph - when the ram air coming in the front provides enough air flow. I will assume your radiator fins arent clogged with insects or leaf bits.
The reason the 413 came with a 7 psi pressure cap was because the higher pressure wasnt needed, and because its top radiator tank was fairly tall, and the extra pressure will result in the top tank flexing more where it joins the top of the core. Mine leaked at that point when I first got it. So i use the 7 psi cap. I have a 160f thermostat in it now, since it spends its entire year in the southern U.S. [Its sitting 8 miles from Mexico at the moment]. I have also had the 180f and the 195f thermostats at different times, and they all worked find, even in Texas in the summers. i had no overheating, lost no coolant - just the wtr temp gauge pointed to different parts of the gauge. Left 1/3rd for the 160f thermostat, in the middle with the 180f, and in the right 1/3rd with the 195f. If it wont work with the 180 or 195 and a 50% mixture, then something still needs to be taken care of.
Are you sure the radiator is the correct one? I will try to find the 7 digit mopar number on mine (its on top of the top tank, a mirror is needed) and post it here. That radiator is a big thick heavy thing.
I have had to replace the sender for the mopar temperature gauge twice. Once because it read too high - from old age I guess, and once becasue it read too low - and the contact was coming loose from the element inside. This was after I had bumped it with something. I had added a mechanical water temp gauge (easy to do with the 413 water pump housing) so I knew the mopar gauge was faulty both times.
I also added a mechanical oil pressure gauge - which gave me peace of mind the day the mopar oil pressure sender died on a vacation. The new mopar sender wasnt too expensive, its the same one used on the vans, pickups, and cars, from the 60s up till at least the later 70s.

And right now I am using a 25% antifreeze to 75% water mixture. Water conducts heat a little better than antifreeze, and doesnt expand and as much when hot. i still dont have a boil over problem, and like I said, it gets used in S. texas, 250 miles south of San Antonio. When I was using the 180f and 195f thermostats (all of them the 'skirted' type) I used a 50% antifreeze to water mixture.
Driving in the summer, with the air being 100f in the shade, and us being on a dark macadam surface, the motor oil temp will get up to 260f and stay there. This doesnt hurt anything, at least it hasnt cause any problems yet.

[ClydesdaleKevin]

Sent: 6/27/2007 7:19 AM

Here is my 2 cents on this:

When we bought the Ark, she had the 413.  The temperature guage on the dash, the stock one, was reading very hot!

So, I had the radiator recored making it a 4 row core, and replaced both radiator caps with new 7psi caps, and flushed out the motor while I was at it  (there were 2 on our radiator...and regardless of what the radiator shop told you, I would stick with the stock 7psi caps...the 413 is a marvel of engineering, and the engineers definately wanted a 7psi cap used)...it still was reading hot on the guage.

So, I replaced the water pump, hoses, and fan clutch with a centifugal clutch that also had a thermostat...it still was reading hot on the guage!

So, I replaced the thermostat with a Summit Racing skirted 160 degree thermostat...it was still reading hot on the guage!

I was thoroughly confused at this point!  So, I figure, it must be the timing, or the carb is running too lean, or any number of other possibilities...

But...there was one other thing I wanted to try first:

Since the whole cooling system was now more or less new, the only thing left to replace was...you guessed it...the dash temperature guage!

I didn't remove the stock guage...I added a new mechanical guage to the dashboard!  The water pump housing on the front of the 413 has a couple of extra plugs/bungs, probably for other applications.  I simply threaded the new sender for the new guage into one of these bungs.

The result?  The new guage read a perfect 170 degrees!  The hottest it ever got, pulling our van in the middle of summer up big hills and mountains, was 190 degrees.  The stock dash guage was still reading hotter than hell...but the new guage was telling me all was well.

I drove the Ark for 2 years, over 20,000 miles, and the stock dash guage the whole time was telling me it was running hot, but the new guage said all was well.  I never burned up the motor, I never blew a head gasket, and nothing ever overheated.

Conclusion?  The dash guage, or the stock sender, was bad.

So, after replacing all your cooling components, try an aftermarket guage and see what it reads, before you spend a whole lot more time and money trying to track down demons that may not exist.

Good luck!

Kev

[MSN Member]

From: Catalina362
Sent: 6/27/2007 8:17 AM

Thanks for all of your good advice. I will add an aftermarket guage to check the heat more correctly, my guage could be bad. I will get one of the thermostats that denisondc mentioned. I still want to replace the fan clutch just incase on the road it goes out. I am taking a 7000 mile trip across and around the country starting July 7th 07 and am trying to get ready for that trip with this motorhome. Thanks again for your help. I will let you know how it works with the new gauge and fan clutch.

Denisondc could you tell me where you got the dash guage rebuilds. I would like to fix that as well as add a new guage to make doubly sure. I am prety shure that my radiatior is the rite one. It to had two filler holes, and has a huge resevoir on top. It's been redone more than once but I think it is rite, becasue I had it on a 4300 mile trip from LA to Idaho and it didn't have any trouble until the last 100 miles when It got hot and has been saying it is hot all year since then. Thanks again for all of your help.

[denisondc]

Sent: 6/27/2007 9:36 AM

I didnt rebuild my dash gauges, but replaced the sender unit for the water temp gauge, and the oil pressure sender for the oil pressure gauge. The original 5 volt 'limiter' that drives the gauges seems to still be working. The two senders were easy to find; I just told them I had a 72 dodge with a 440 in it. The water temp sender was in the middle of the side of the engine head, between the 2 and 3 cylinders on that side. It can be on either head, though usually only one head has the hold for it. The oil pressure sender just threads into a fitting at the top-rear of the block, above the bell housing.
I have since harvested a complete Winnebago instrument cluster from one of the junkyards, for the day when something dies on mine. I expect it will be the rocker switch for the headlights, or the speedo itself.
My mechanical water temp gauge was a cheapie from JCWhitney, and lasted about 10 years, before it began reading low. I got another cheapie -used- from ebay, and that is what is on the RV now. My mechanical oil pressure gauge has worked fine since I installed it in 1991. The fuel pressure gauge and the fuel pressure isolator were both by Autometer. The isolators arent cheap unfortunately. I also added a vaccum gauge, a tachometer, and two oil temperature gauges; one for the motor, one for the tranny. They needed to have places for the 1/8th p.t. sensors to screw into. I added these fittings to the oil pans when I happened to have them off. I have an oxy-acetylene torch, which makes such little jobs pretty easy.
The next time you have access to it, I would recommend you pull the speedo cable off the back of the speedo head, and pull the inner cable out. It will probably be dirty and sticky. I undid the bottom end of the cable at the back of the tranny, and dripped Marvel Mystery Oil down into it, (sea foam would work just as well and is easier to find). I worked the cable in and out, cleaning it off each time it came out. I started putting thin oil (3-in-1) down the inside of the cable housing, and kept up my cleaning until the puddle of oil that dripped out the bottom end of the cable was not black anymore. I let it drip overnight, put a light coating of vasoline onto the cable, and put it all back together. I need to do this again, as its been 16 years since I did it - and it really needed the cleaning at that time -when it was already 19 years old.

[MSN Member]

From: Catalina362
Sent: 6/29/2007 3:57 PM

Well I finally replaced the Fan clutch after having one strip the stud hole. After replacing the clutch on the 413 I put a new mechanical gauge on it to get a second opinion on my heat problem. I went for a test drive and ended up overheating again. Both gauges work fine. The dash gauge was reading the same as the new mechanical gauge. After replacing the thermostat, water pump, hoses, guage, flushing the engien, and having the radiator cleaned and presure checked I am thinking it is still the radiator. I broke down yesterday June 28th and took it to a mechanic. I don't know what the problem is still but I will hopefully have an answer by tuesday of next week. If not the radiator it might be a backward flowing water pump if that is possible. I thank you for your help, and I will let you know what the exact problem was when I find out.

[ontheroadagain]

Sent: 6/29/2007 6:06 PM

i had the same problem with a jeep once when jeep switched to a single serpentine belt they reversed the water pump rotation and the owner had replaced the water pump that was the older style that turned the wrong way but i dont think mopar did that with the 413 maybe the pump was made wrong ?

[MSN Member]

From: Catalina362
Sent: 7/3/2007 9:27 PM

I have gotten the motor home back from the Mechanic. It still overheats. I have had the radiator cleaned out now 2 times(it's clean). I Think it might be the distributor or vacume advance. Has anyone had any trouble with heating due to vacume advance in the distributor? If so what did you do? Pleas respond !

Also I have had it checked for head gasket leaks and no leaks were detected. Then opening the block petcocks there was flow to both sides of the block with fluid. No chunks or debree came out.

[ibdilbert01]

Sent:  7/3/2007  100:00 PM

Make sure your fan shroud is on.  Mine was off and the motor ran hot.  I put it on and couldn't believe what a difference it made!

[MSN Member]

From: Catalina362
Sent: 7/4/2007 12:43 PM

The first time I had the radiator recored recored 2 or 3 weeks ago the radiator shop said it was 33 % plugged. They supposedly cleanded it an presure checked it and it came back good after cleaning. I put it in and it still overheated. Then I took it to the mechanic because I was done with everything possible to fix the problem. The mechanic took out the radiator one more time and had it cleaned once again, this was last week, and it was still 33% plugged. He had it cleaned and checked it putting it back in. I am not sure if it is the radiator. I do think I got cheeted on the first cleaning but this second one I think did a good job. I got a quote on a radiator from yet a third guy who said it would be about 600 dollars. I opted to keep hunting because this radiator is flowing, and it is the correct size (huge), and it doesn't leak. It got us to Idaho and back from L.A. so I am not sure We removed the mufflers to get a sense if there was somethig blocking the flow of exaust to make heat catch in the engine. Still haven't gotten to check that fully because I have to have the exaust rebuilt and then replaced to get the results of that heat source. We have changed the timeing a little and set it 5 degrees before top dead center, this with the Headers and 4 barrel holly carb. When I get it put back together with the exaust then I will test drive it again and see if it still has a heating problem. Thanks again for the help. I will keep the radiator as a suspect if all else still fails.

Thanks ibdildbert01 for your help, the fan shroud is connected to the radiator it doesn't come off and the fan fits rite within the shroud. I think it is supposed to be that way,and I haven't changed any thing cosmeticaly to the radiator.

[bluebird]

Sent: 7/4/2007 5:43 PM

Did you have this problem before you installed the headers or carb? If the engine is running lean or too rich it will over heat. Do the headers glow at night? What do the plugs look like? They should be a very light tan. If they are white it is too lean, even with unleaded fuel. Dark brown or black indicates a rich mixture, and the headers will glow. Thay should have been able to flow that raditor when they had it. The raditor shop should have flowed it after they were done cleaning it.

Charlie

[Slantsixness]

Sent: 7/5/2007 4:55 AM

How exactly did the radiator shop determine that it was 33% blocked?

These radiators have a built in restriction due to the design... a brand new radiator will have restriction between input and output.

33% blockage would mean that a third os the radiator core was clogged. That seems to me, to be too much of the core blocked to operate efficiently, however if they "flow tested" it from the input to the output (which is from the bottom inlet to the top outlet) that under perfectly normal operation, the flow would be about 33% restricted. It's not the "flow" that matters, it's the processing (cooling) of the volume of coolant within the radiator that does. The big block water pump, and radiator design is not very efficient, but it does the job. You DO have the correct water pump (cast iron) on the 413, right??

So, I don't see a problem there, theoretically, that is.

Timing, running rich, bad fuel, bad sensors, carb not jetted correctly or a sticking choke even... or something blocking the air into the radiator (like an electric fan that turns the wrong way, or a trans cooler that's clogged with bugs....)

Tom

[ClydesdaleKevin]

Sent: 7/5/2007 7:31 AM

When you had the radiator recored, did they really recore it, or just flush it out and clean it up?

When they recore a radiator, they actually cut out the welds on your bottom tank and top tank, throw away the old core (the part with all the tubes and cooling fins), and then braze in a whole new core, reusing your bottom tank and top tank...if they are a good shop, they'll paint the top and bottom tanks as well after assembly, and it will end up looking like a brand new radiator.

The typical cost of recoring is anywhere from 200 bucks to 600 bucks.  The reason I'm asking is because you mention the 600 dollar figure from one radiator shop, and if was recently fully recored, nothing about the radiator would ever cost you that much.

Kev

[MSN Member]

From: Catalina362
Sent: 7/5/2007 12:04 PM

I have replaced the plugs in the last three weeks, but the old plugs were brown to black grey, They showed signs of running rich so we changed the timing to 5 degrees before center. I bought the motor home with the headers on it and nothing seemed to be wrong for the first two years of driving it, including the trip to Idaho from LA. I haven't noticed them glowing at night. Today July 5th I am having the exaust done to see if there was anything wrong down there with the heating problem. Thank you charlie for your sugestions. Tom I am not sure how the first radiator shop determined the blockage. The reciept states that they rodded out and tested the radiator repairing something (unspecified), and that it was 30 % plugged. They told me it was clean and ready to go so I put it back in. The second radiator shop who did it was one the mechanic sent it to. He didn't do it himself, but it still was 33% plugged he said and when he got it back he said it was good and put it back in. The radiator felt hot all over not just in one place the last time I drove it so it is flowing evenly but I can't give any better explaination than that. After the muffler is done I am going to test drive it again, and if it still has heating trouble after the muffler replacement, and change of timing, then I will take the radiator out one more time and get it recored not just cleaned or rodded out. Kevin the radiator has not actualy been recored yet. When I took it to the second mechanic He said at first he would have a new one built for it but then he said this radiator guy felt it only needed a cleaning and it was good to use as it was. Like I said before if this last set of changes doesn't work then I will take the radiator out and have it recored and rebuilt fully. Thank you all for your comments.

[ClydesdaleKevin]

Sent: 7/5/2007 2:19 PM

Some advice on having it recored:  First, shop around.  An old established family place will be a lot cheaper...I think I paid over 400 bucks to have mine recored, and folks on here said I was ripped off and could have gotten it done a lot cheaper.  Second, go with a 4 row core if you are having it recored...it will increase the cooling capacity a LOT!

If everything else checks out, then I'd say recore it, and go with a 4 row core.

Kev

[denisondc]

Sent: 7/5/2007 5:29 PM

Can I assume your thermostat is the type with the 'skirt' on it, that moves down in the thermostat housing - to close off the 'warm-up circuit', where water is pumped back through the engine block, instead of to the radiator?

[ClydesdaleKevin]

Sent: 7/6/2007 8:01 AM

Dave's right!  I don't know why we didn't think of this before.  The thermostat on a 413 is different from a thermostat on a 440, although the 440 thermostat will fit, and some mechanics that don't know the difference will use the wrong one!  The 413 requires a special thermostat that has a "skirt" on the base, that channels the water differently through the heads, and blocks off/restricts water to the radiator during warm up.  If you try to use a flat 440 "regular" style thermostat, it will overheat!  For that matter, the skirted thermostat is so necessary to the water flow, that taking it out and using NO thermostat will also cause it to overheat!  Trust me, been there done that with the Ark!

You can get the skirted thermostat from Summit Racing, and I think there is another place on here as well where you can get them...you'll have to find the thread.  I used the 165 degree thermostat from Summit, and the Ark never got over 185 degrees under any conditions.

I searched through the message boards, and couldn't find the info for the thermostat, so I went to Summit Racing and found it for you.  The link is http://store.summitracing.com/partdetail.asp?part=MIL%2D16405&view=32&N=700+150+4294903544&appfilter=1#Application
 
Kev

[MSN Member]

From: Catalina362
Sent: 7/6/2007 10:41 AM

Thank you Kevin I did see that last message board posting before but forgot where I put the part number As soon as you reminded me in this last message I remembered it and and talke to them (Summit Racing). Thery were very helpful. I found a thermostate here in southern california at Blairs Speed shop in Pasadena. The thermostats are a Mr. Gasket brand. They can be found at www.mrgasket.com. I bought two of them they are the same exact things as what was in the picture. I will replace it again, right now. Thanks again for the reminder.

[DaveVA78Chieftain]

Sent: 7/6/2007 12:28 PM

Hmm

Always thought both the 413 and the 440-3 used skirted stats.  Been a lot of discussion about that on this board

Enter thermostat in message search and you will see a lot of info on the subject.

Dave

[ClydesdaleKevin]

Sent: 7/7/2007 4:55 AM

You might be right, Dave...I've never had a 440, just the 413.  I do know that if you go to a NAPA and give them a part number, it crossreferences to the 440, and they give you an unskirted thermostat.

Kev