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Discussion Starter #1 (Edited)
I just got this dart about 2 months ago and been getting stuff buttoned up on it.
I noticed the overheating problem and was looking around and seen that the after market fan was 16" diameter and the shroud opening is like 20", Plus the fan was setting back too far to be in the shroud. So I was crossing my fingers and changed the 195 t stat to a 160 and I took it down the road and it got to 160 and then kept climbing.
Its a 360 engine that built alittle and Im guessing about 275-300hp and the car has the stock radiator in it that appears to be flowing great when when I remove the cap and look at the flow inside the radiator.
Anyways,,, I knew it wasnt going to help to change the fan set up since it does it at 60mph even with 3.23 gear.
But I changed the fan set up any ways to a electric dual fan set up that will suck up a full sheet of sand paper 16" away from the radiator into the radiator and I put some water wetter in it too and it still over heats while driving.
I dont see any oil in the antifreeze and I dont see any water in the oil either.
Anyone got suggestions Please?
 

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Have you looked at the water pump? I had a new high volume FlowKooler pump in mine that went out after 18 months of use. It was the last thing I checked cause I couldn't believe a new pump was bad.
 

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Discussion Starter #3
If the water pump was bad...wouldnt it not flow in the radiator very good if not at all? Cause the water rushes by when you remove the cap and look into the radiator.
Thanks for your help cause I need it.
 

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Does it get hot in slow traffic? or at highway speeds? If it gets hot in traffic its not getting enough air and you may want to put on a smaller pump pulley to overdrive the pump at low speeds. If it gets hot at speed, does the bottom hose have a spring in it? if it doesnt it may be sucking shut and keeping coolant from flowing back into the motor. Is the thermostat working? You said it was a new 160. Did you test it before you put it in? Is it a HP t-stat or stock?How hot is it getting?
I work for a cooling company and I ask these questions to try and help. Let me know and I'll try to help you solve this problem or at least bring it under control.
 

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Discussion Starter #5
When the engine is started cold and is running the temp will go from 0 and and it will get to 160 and then the temp still rises but not at fast as it does before the t stat opens. Yes the bottom hose has a spring in it and it gets hot setting still, slow speeds and highway speeds. Its a stant super stat and It does open at 160 cause I tested it first with my raytech temp gun. You asked how hot its getting....I have only let it get up to 205.
I cant figure it out. I would think the stock 318 radiator would be sufficent enough for a 300hp motor.
Thanks for your help!


Does it get hot in slow traffic? or at highway speeds? If it gets hot in traffic its not getting enough air and you may want to put on a smaller pump pulley to overdrive the pump at low speeds. If it gets hot at speed, does the bottom hose have a spring in it? if it doesnt it may be sucking shut and keeping coolant from flowing back into the motor. Is the thermostat working? You said it was a new 160. Did you test it before you put it in? Is it a HP t-stat or stock?How hot is it getting?
I work for a cooling company and I ask these questions to try and help. Let me know and I'll try to help you solve this problem or at least bring it under control.
 

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Discussion Starter #6
I have been thinking about my timing.
I dont know the specs on the engine but its got a rough idle cam and it has a 670 avenger on it and a performer intake with headers, Thats about all I know about the engine.
Im wondering what my total timing should be close to and what my base timing should be.
I dont hear any spark knock at all, Just throwing that out there.
Thanks
 

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Take an old thermostat and gut it. Put that gutted one back in.I want to eliminate the thermostat as a problem. I would check the gauge to. Is it a mechanical gauge or electrical? I'm just gonna throw some stuff out here..........the radiator although you say you see flow may not be the best of shape. Maybe having it cleaned and pressure checked would be another way to go. The impeller in the pump may be a problem. A motor getting hot at idle or at speed tells me the flow is not right. At speeds the airflow should easily bring temps down.
Timing should be in the 34-36 deg area.
 

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I forgot about the spring in the bottom hose..I don't think I have a spring. Maybe way I'm overheating. Thanks
 

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do a pressure test first,don't forget the cap.even if you don't have a leak a loss in prssure can cause it to overheat
also check for "cool" spots in the rad looking for a clog.
 

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Discussion Starter #10
The guages are mech and they are right. I checked them with my temp gun and the temps were consistant to each other, I am getting lots of different heat ranges though on the radiator core. I will have 137 in spots and the numbers range all over the place but dont go over what the gauge is reading, Both hoses are temping about 5 degrees difference. Pulled the t stat out and temp went up alot faster and topped out before I shut it down at 205 but got there alot faster and would have kept climbing if i didnt shut it down. About the impeller,, If the impeller was slipping on the shaft wouldnt I have a low flow rate going through the radiator? Cause If I rev the engine just alittle its ciculating enough to splash water out of the fill neck..
Its coolng off right now.
I was letting it run with the cap off to try to purge air out of the system If there was and it kept shutting down at 205 and now sounds like it hitting on 7 cyl so Im letting it cool off. Hope nothing screwed up from doing this!!!

Seems like the t stat in kept it from reaching these temps alot better.
Take an old thermostat and gut it. Put that gutted one back in.I want to eliminate the thermostat as a problem. I would check the gauge to. Is it a mechanical gauge or electrical? I'm just gonna throw some stuff out here..........the radiator although you say you see flow may not be the best of shape. Maybe having it cleaned and pressure checked would be another way to go. The impeller in the pump may be a problem. A motor getting hot at idle or at speed tells me the flow is not right. At speeds the airflow should easily bring temps down.
Timing should be in the 34-36 deg area.
 

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Discussion Starter #11
It has a new stant cap on it too 13lb.
Like did see cool spots in the core when I was checking it.

do a pressure test first,don't forget the cap.even if you don't have a leak a loss in prssure can cause it to overheat
also check for "cool" spots in the rad looking for a clog.
 

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205 is nothing to worry about it will not cause any damage,water boils at 212 and higher under pressure.
You should be safe in the 220 range, with a 13 pound cap it should boil over untill the 250 range (don't try it)
What is the temp of the top rad tank and lower tank?
The rad maybe partly plugged
 

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Take you heat gun and test different areas around the block and heads...they all should read about the same...if not you probably got air pockets in the block...I would also pull your water pump and make sure it is an 8 vane one and not a 6 vane one...put your thermostat back in...with the bigger hole it was flowing too fast...I would also look at a e-bay three core or 2 core with 1" tubes aluminum one..
 

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imo hit up your local speedshop and get an allstar racing rad. lots of guys use these in their street cars because their a good rad at a cheap price. up here in canada I can get one for like 150 bucks
 

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Pull your radiator and have it cleaned out. Looks pretty on the outside but it might be ugly on the inside. Test your t-stat on the kitchen stove in a pan of water, it's one of the most accurate ways to test it. I agree with Bremeric, 16# cap. While you have your rad out it would be real easy to pull your pump and take a look at the impeller. Also, if the coolant passages have a lot of scale in them it could cause some heat transfer issues from your block to the coolant.
 

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Discussion Starter #18
After it cooled down I found that a spark plug insulator was burned through arcing on my header, Fixed now and Yes it is my radiator! This might sound funny but Im pretty happy thats the problem and not something wrong with the engine.
I took my temp gun and ran it all over the radiator again and found all across 3/4 of the bottom I was getting temps of like 130-135 and then on the top hose side 191-192 and the straight across was 155-165-and up and then righ in the location of the lower side was around 190-192, I could almost trace the flow of water with the gun.
Im just going to buy a new radiator and re-use my fans cause there really pulling some air! Like I said before...I can take a whole sheet of sand paper and this is one of them 11 x 14 sheets?? Not exactly sure of the size but I can turn them fans on and put the sheet up close to my bumper and its sucked right into the grill. I like the twin motor sound too, lol.
I want to thank you all for your help and advice....With out you guys giving me the info you did I wouldnt have found it so quick and it didnt cost me nothing ! Thats always a plus.
Thanks and hope you all the best!
 

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When you put the new radiator in...........pour about a 1 1/2 gals of coolant into the block through the filler neck on the manifold. Then connect up the top hose and finish filling thru the radiator. You are less likely to push an air bubble into the system this way. You will know soon enough if you do get a bubble.......the motor gets real hot real fast.
 

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I have been thinking about my timing.
I dont know the specs on the engine but its got a rough idle cam and it has a 670 avenger on it and a performer intake with headers, Thats about all I know about the engine.
Im wondering what my total timing should be close to and what my base timing should be.
I dont hear any spark knock at all, Just throwing that out there.
Thanks
I HAD A 318 WITH 360 HEADS , NICE CAM . 300 + HP. I HAD THE SAME PROBLEM. I HAD A 650 CARB ON IT AND THE FACTORY TIMING. I WENT TO A BIGGER CARB ,750 , AND PLAYED WITH TIMING TO FIND ITS SWEET SPOT AND THAT SOLVED THE PROB BOB.
 
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