| From | Message |
Vanschlick
Dodge Dakota
JOIN HERE
7/11/2007
23:48:03
|
 Subject: Dakota 4.7 Overheating issue
IP: Logged
Message:
Coming home sunday on a hot day, about an hour drive - 45 minutes in my check gauges light comes on - trucks hot. (4.7 dakota quad cab 2 wd)
Pull over and let it cool down drive about a half mile to station and cool down fill with water and try to continue on, no go! Started climbing pretty fast so I went back to the staion and parked it just as the check gauges light was coming on again.
Got a ride home and came back in the morning, took off the cap hoping there would be an air pocket but coolant level was full. Started it up and after getting to 210 it started to climb pretty quick again. The top hose was hot as hell while the lower one was cool enough to easily put my hand around and hold it. So I figure its got a blockage, and order a thermostat.
Changed it and put coolant back into the block through the top radiator hose with it disconnected from the radiator and held high in the air, then filled the radiator in the same manner.
Same result, gets to 210 then starts to climb past that, still seems like a blockage, as the bottom hose is cold to the touch. Checked the old thermostat by boiling it - opens just fine. took off the bottom radiator hose and filled it from the top with water, flows right through.
Had changed my water pump about a year ago (at 100k miles, truck now has 130) because it was staring to make noise like the bearing was going out. So the one thing (other then a cracked or warped head) that could be wrong with it is maybe the impeller came off the water pump on the inside.
A mechanic friend of mine says he thinks its a cracked head for sure, that a crack in the head could creat a air pocket that would disrupt the flow of coolant. I have yet to pull the water pump, and dont even want to think about it being a cracked head...
I guess theres some test kit that will show if there are exhaust gasses present in the radiator, but its like 60 bux - any other way to tell for sure? any ideas - suggestions? whats a head gonna run me 2- 3 k? saw something about crate motors being like 6500, by the time you get it installed thats way more then my truck blue books at...
good ole disposable dodge yay
|
TexasTodd
Dodge Dakota
JOIN HERE
7/12/2007
05:21:10
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
Does it run O.K. when not overheated? Then it ain't no head gasket failure.
And my 4.7 hasn't had any belt driven clutch fan on it for over 5 years, so it ain't the clutch fan.
Did you Bleed the system after each refill?
Good luck.
|
TexasTodd
Dodge Dakota
JOIN HERE
7/12/2007
05:25:39
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
Does it run O.K. when not overheated? Then it ain't no head gasket failure.
And my 4.7 hasn't had any belt driven clutch fan on it for over 5 years, so it ain't the clutch fan.
Did you Bleed the system after each refill?
Good luck.
|
daddio
Dodge Dakota
JOIN HERE
7/12/2007
09:24:19
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
i'd say if it is not missing it's not a head gskt. pull the tstat out and try that. if it still gets hot, then with the stat still out take the rad cap off, start it and see if you get any flow. if no flow it's the pump. unless the rad is totally plugged but thats doubtful.
|
Shoe
GenIII
7/12/2007
12:38:22
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
If the head was cracked or the head gasket was blown it would smoke and probably have water in the oil. Change out the water pump. I know that my 3.9 went through a couple of crappy ones. I do not know how the 4.7s treat people.
|
Vanschlick
Dodge Dakota
JOIN HERE
7/12/2007
17:24:52
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
It does run fine, but that doesnt eliminate a crack in the head between the combusion ports and a water jacket. And its defiantely not the t-stat (changed it already and tested the old one, it opens) or the radiator (filled radiator from the top with bottom hose off and it flows through just fine)
so either I spend a little time pulling the water pump, or buy a block test kit for 50 bux to test for exhaust gas in the coolant, kinda burned out right now and its hot as hell here today...
|
Kowalski
GenIII
7/12/2007
18:05:46
|  RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
How would a crack like that prevent the coolant from circulating ?
Lead, follow, or get out of the way
|
Vanschlick
Dodge Dakota
JOIN HERE
7/12/2007
19:20:30
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
yeah, thats what Im saying...
Ill update this when I have pulled the pump - maybe tonight after it cools off - pump isnt that old - but maybe (fingers crossed) the impeller came off the shaft and its free wheeling in there!
|
DSW
Dodge Dakota
JOIN HERE
7/12/2007
19:49:37
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
I don't know how easy this is going to be on the 4.7, but fill the radiator up and leave the rad cap off. Start the truck and check for water flow and keep topping off the antifreeze to purge any trapped air. If you have a blown head gasket of cracked head leaking air into the coolant, you will see micro bubbles pooling up in the radiator cap and flowing with the water, not big bubbles from trapped air, really small bubbles like soda bubbles. Problem with doing this with a 4.7 is the cap being in the rad hose. Anyway, I have seen a few cracked heads/blown head gaskets and this test revealed the air escaping into the coolant.
|
Vanschlick
Dodge Dakota
JOIN HERE
7/12/2007
22:05:13
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
there are some tiny bubbles in the coolant - but not til after it gets warm, and the coolant does not flow though at all, wich is verified by the fact that the bottm hose is cold while the top one is hot.
|
daddio
Dodge Dakota
JOIN HERE
7/12/2007
22:18:23
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
waterpump
|
Vanschlick
Dodge Dakota
JOIN HERE
7/13/2007
02:16:18
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
water pump impeller cracked in half - housing where pump mounts is damaged from the impeller...
have to wait and see how much and how fast I can get that housing, and Im gonna change the clutch fan (its definitely a clutch fan) while Im at it. may even throw a new radiator cap at it too.
as long as the original overheat didn't damage the head or gasket I should be golden.
Thanks for all the input.
|
GraphiteDak
GenIII
7/13/2007
11:25:57
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
I was a little late on this one but it sure sounded like a pump to me.
Good thing you got the problem found. Them gaskets on the 4.7 are TOTALLY different than those on the older engines. They are multi layered METAL gaskets like ATV engines use or them EXPENSIVE ones you buy to turbocharge an LA engine LOL!
You wont know if the damage was done until you fix the water pump and just try to drive it.
Let us know either way because we don't hear too much about someone overheating their 4.7 that often and it DOES have aluminum heads and typically a good overheat can warp aluminum pretty easily but maybe with the gasket design and all... Just let us know. :)
|
Paul
Dodge Dakota
JOIN HERE
7/14/2007
16:53:15
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
Don't know much about engines, but last year my 2000 4.7 dakota was overheating on regular highway driving. Took it to Dodge dealer, and they couldn't find the problem. someone told me to replace the radiator cap, so i bought a $2.00 cap and problem solved. It is worth a try.
|
Vanschlick
Dodge Dakota
JOIN HERE
7/14/2007
20:51:25
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
definitely not the cap - the impeller in the water pump was cracked in half which damaged the housing the pump mounts too... cost me $280 + $35 gasket, not to mention $100 for the pump and another $70 for the clutch fan, its on its way out too. I will spend another 3 bux on a radiator cap just for good measure.
Waiting on the water pump gasket atm, will have her back on the road monday evening. Keeping fingers crossed the oevrheat didnt do aything to the heads,
|
Kowalski
GenIII
7/15/2007
08:50:38
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
A bad cap definitely won't stop the water from circulating; it just means the system won't hold as much pressure - so it would boil over more easily. Completely different cooling problem.
Lead, follow, or get out of the way
|
Vanschlick
Dodge Dakota
JOIN HERE
7/17/2007
07:28:52
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
Ok - so when the water pump went out it took out the timing cover, impeller kept grinding on the housing til it made a hole... then where did all that plastic and metal end up - you guessed it in my radiator... was lucky enough to get one for 200 bux (new Mopar)
So new radiator, water pump, clutch for the fan and the whole front cover for the engine (what a bitch that was) harmonic balancer, ac, alternator - everything had to come off... with parts - coolant etc I paid about 640 or so... good 10 hours labor and it runs like a top... runs at a cool 190 now!
this problem had been going in for awhile so my engine was runing warm (not hot- but over 210) I noticed right away its much more responsive on the passing gear... plus if im not mistaken with the thermostatic clutch going out if was prolly robbing some HP too...
thanks for your help and advice and if your check gauges light comes on because your running hot - PULL OVER - even though I had to spend a lot of time and over 600 bux on this repair - it would be a lot worse if I had warped/cracked a head, or blown a head gasket.
|
fred
Dodge Dakota
JOIN HERE
7/18/2007
19:15:54
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
I having the same problem with my 2000 4.7 Durango. I pulled the water pump only to see that timing chain cover behind the water pump propeller was missing a big hunk of the cast aluminum where the water should be flowing. The strange thing is that the plastic propeller for the pump looks good. I have replaced the radiator purchased a new timing chain cover (from Mopar that came with the water pump and thermostat/housing for $262), new clutch fan and new upper radiator cap/hose.
Now my problem is that I can not find the correct installation tool for the damper (Harmonic balancer) on the front of the crankshaft. It seems that Dodge did not thread the crankshaft all the way out on this one and now I need a special tool or bolt to reinstall the damper the size is M14 X 1.50 X 200mm
Please help.
|
TexasTodd
Dodge Dakota
JOIN HERE
7/18/2007
22:30:42
|  RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
Vanschlick,
You may not have the bigger radiator w/ the towing pack. Did you install a 180 degree t-stat?
Others, and myself, have been going fan clutch and fan less for years now, now hot temp issues.
Your 4.7 does have the factory electric right?
|
daddio
Dodge Dakota
JOIN HERE
7/18/2007
22:42:31
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
i don't know about the 4.7 but, other engines with similar design, if the waterpump impeller goes through the timimg cover. doesn't that cause coolant to leak into the crankcase?
|
Vanschlick
Dodge Dakota
JOIN HERE
7/18/2007
23:16:21
| RE: Dakota 4.7 Overheating issue
IP: Logged
Message:
gonna reply to the three last posts here...
fred - took about 3 hours and a hell of a lot of wd 40 and carb cleaner to coax that harmonic balancer off - and I didnt actually reinstall it a buddy who is a mechanic for the county came over and did that part for me... I will find out what he used... he had it back on before I got home from work.
TexasTodd - I do in fact have the tow package, it has a thermostatic clutch fan and an electric fan, but runs so cool now the elctric fan does not even kick in and I went with the stock thermostat because until this problem I had never even run close to warm...
daddio - the impeller wore down the front of the inside of the housing where the water pump mounts... the design of it to move the water is like the inside of a snail shell, so what it did was wear off the outside layer so there was a big hole, wich greatly reduced any chance the water would flow- but it did not go all the way through - the impleller is plastic so it not likely it could go all the way through about an inch of aluminum before you would have over heating issues.
|
| | P 1 Next Page>> |
