My project has a Chevy 350...an 'early' block with late model heads...I found a serpentine bracket off a junk yard truck, so I'm running one belt. The motor and all accessories are new including the water pump & thermostat (3x!). The timing is set correctly and I'm running a "Griffin" Aluminum radiator especially made for this type conversion. I'm using a high CFM electric fan that is controlled by a thermostat that IS turning it on at 180 degrees.

I have pressure tested the system AND even "Block Tested" for the presence of exhaust gases (There were none, thank God!). My radiator hoses are the high dollar bendable aluminum (so they won't collapse). I DO have fluid flow through the radiator...

I do have a reserve/overflow tank connected and in use.

I AM running headers & I do have both the AC condenser and an oil/tranny cooler in FRONT of the radiator...but sitting still I DO have good flow through the radiator...

Finally, I have 'burped' my system 4-5 times on my (very) steep driveway to get all of the air out...

So what's my PROBLEM??? The d*** thing OVERHEATS 10 MILES AWAY from my house...everytime...

I don't trust the gauge so I put new one in that is part of the radiator cap...it will jump up to 220 as soon as I stop for a traffic light. I've had this thing to the shop and played (Let's try this...at the shop rate!)...AND untold number of hours of my own...I'm ready to drive the thing off the nearest cliff!

HELP!

I seem to remember something about the serp setup water pump being opposite rotation from a V-belt setup? Something about the path of the belt and such? At any rate, are you running the "correct" new water pump? Just a thought...

Is it lean? borrow a infared thermometer and check the ports. 600-750 was normal on mine. Is it shrouded? Swap a mechanical fan on it and drive it 10 miles.

Good catch on the reverse rotation h20 pump. That would do it.

I had the same issue with mine. I had a mechanical fan and it would start boiling the water out when I was crawling. I added a black magic pusher fan and originally had it thermostatically controlled, but the controller died and I just wired it to a switch. Since running both, it hasn't overheated since.

It is a good rad, a Mepco high efficiency 3 row.

There is truth to the serpentine drive spinning the opposite direction to the v-belt drives. The blades are pitched the other way. I learned this the hard way. The motor got so hot during the test run that the paint on the rad became wet. Scored the bores in the motor.

You can tell if you have the wrong fan on your motor by putting your hand in front of the rad. It should be sucking not blowing. It's always so obvious after the fact.:)

thanks for the replies...

I too thought of the water pump reversal thing...however, I just thought I'd progressed to the point of grasping at "straws"...hummm, perhaps I AM to that point.

So...the ONLY way to be sure...would be to find a chevy truck motor that came stock with a serpentine setup...and buy THAT water pump?...or does someone KNOW the answer already?

Ironically, I've purchased two more water pumps and returned them...cause it 'seemed' to me I "had flow"...but to be honest, I couldn't REALLY tell you which direction. One note on the water pump idea...the water pump PULLEY that I have...is SMOOTH; not RIDGED...meaning I have it [the belt] going around it in the correct direction... It comes up from the crankshaft pulley, crosses to the LEFT side of the water pump pulley, then up and over the top to the right, to the Alternator pulley. To be clear, as it travels over the water pump pulley, the ridges of the belt are to the OUTSIDE and visible...perfect for the smooth pulley.

One guy mentioned ck'g the direction of the flow through the radiator...trust me ...it sucks; and sucks well...I have a good electric fan from one of the 'names'.

Heater hoses still hooked up? is the electric fan actually blocking the air at high speed? Have you shut off the fan at speed yetto see what it'll do?

ei have you used an infrared thermometer to check your temps in the engine compartment and around the motor? i'm in ellijay and could come down and try to help diagnoise the p'bm, i'm running a ls2 in my tj and have been where you are---- don't throw it away yet--- it's gonna be sweet when you get it right. mase

This would probably be better suited to the Newbie or General sections, but from the sounds of it, I would vote for the reverse rotation water pump solution.

Once you try that, you may have to re-do the burping etc.

You do need the reverse water pump, get one for a mid 90's chevy truck.

Yep the heater hoses are hooked up...in fact, I was wondering if it could be possible that air was somehow trapped in the system. One thing I failed to mention was an attempt to suck any air out by pulling a vaccum on the overflow reservoir...I DID manage to get 14-15 lbs of vaccum...and saw fluid being sucked into the reservoir [via the sight tube]...so I assumed all air was gone...?

I'm going to call the dealer and ask about the whole water-pump reversal thing...if it's true; I'll begin [again] there.

BTW I've spent hours combing through this sites archives using google advanced search and came up with nothing useful, so again, the comments are greatly appreciated; it's been a VERY frustrating build. Guys who've been doing this for years, have just shaked their head over the issues that have [constantly] come up. But, as my tagline says...the only thing we CAN control is our persistence... When this problem is solved,...all I have to do is figure out how to get better than 10MPG!

Rats! I just spoke with a local dealer...the guy was under the impression that the reverse flow systems didn't appear on the trucks...but on the Camaro LSx motors in the late '80s early '90s. My block is an 'early' one...like mid-80s truck motor, with 'late-model' heads. sigh.

For a quick, cheap 'fix', try a Taurus fan. You need a fair amount of airflow to keep that motor cool.

I've been fighting overheating in my Bronco. I am relocating the trany cooler I mounted right in front of the radiator. I think it is restricting too much air flow.

From your description, the engine is creating too much heat, either from lack of coolant flow, or somthing is not dialed in right. The airflow/rad system sounds ok (or at least close).

Post up the timing details. How much static, how much additional vacuum, and how much centrifugal. Is the vac advance set to manifold or ported, and when is the centrifugal set to come in (what RPM). Do you have pinging at all? How does it drive?

Is it running rich or lean? Do you smell the rich when driving it the 10 minutes?

Do you have a high flow tstat? Normal ones have tiny opening. Did you (or is there) a 1/8" hole in the flange? This will help you burp but doesn't sound to me like your problem.

Is this a new thing which happened on an already running engine, or did this happen after you did the whole project and ran it for the first time?

I agree, triple check that you have the right rotation water pump. I have v belt std rotation in my 350 CJ.

Do you have a coolant recovery tank? In my 350, I had the problem that it would burp the fluid, then when it cooled down, the cooling system would pull air back in, making an air pocket every time.

Just a few thoughts.

BEEN thinking 'bout the tranny/oil cooler combo...also...man, what a PITA to move however! Also been considering adding hood vents [in the top 7 sides] to help with the header heat.
I just don't 'get it'...there must be THOUSANDS of these conversions running around, WITH AC for goodness sake! The Jeep engine compartment isn't THAT smaller than the mid-size Dodge that COMES with a V-8 !...and it has at least an AC condenser in front of it!

Hummm, however, it will NOT overheat just idling...well, maybe it would but I'd have to let it sit there most of the day. So what's that telling me??? Poor air-flow??? From having too many things in front of the radiator?...or from too much 'pressure' in the engine compartment at 45 mph? Both sound crazy to me; & I havn't even added the winch into the mix yet!

The timing is spot on....I've done it myself...then taken it to a pro to make SURE that wasn't the issue.
I'm running a Truck Avenger Holley carb...tuned to the point you'd swear it was FI instead! I have great throttle response and the engine runs great up until I 'sense' it's getting hot. I'm not sure how to express that one...perhaps I hear a difference, but I KNOW when it's getting warm.
Yep I do have a reservoir...although I couldn't tell you if it's sucking air back inside; I guess I could pinch off the vent tube after the motor warms up then let it cool.
And finally, this problem has been with me from the very beginning. It has never not overheated...it just took it a bit longer last winter.

I don't know, maybe I should just TRY a reverse flow pump...what have I got to loose except [another] Saturday morning?

T..........I don't know, maybe I should just TRY a reverse flow pump...what have I got to loose except [another] Saturday morning?


Probably cheaper than diagnostic shop time.

You need a reverse flow water pump-your pulley spins the opposite way now.

also-try retarding your timing a few degrees

How many CFMs is your fan pulling? One of my friends had this problem until he put a pair of 2500 CFM fans on his Jeep.

I have a good electric fan from one of the 'names'.

I went through a couple of elec. fans (permacool and flex a lite) before going with a mech. fan, clutch, and shroud off of a 4.0 YJ for my 350 and now have zero issues cooling. I also have an elec. fan on a switch as a front aux. pusher, but I never need/use it. Beware after you get your initial on road cooling issue (water pump?) straightened out, that your name brand electric fan might not be sufficient for cooling the Jeep in demanding slow-speed offroad situations.

Also, before you put hood vents in, go ahead and remove the rubber strip where the cowl and hood meet at the back, this allows hot air to escape which aids in cooling.


Good luck.

ET, you and the dealer were discussing apples and oranges!! He's right about reverse flow cooling--different engine! What people here are telling you is a water pump listed for an early block that used V-belts turns in one direction, while the water pump for a serpentine belt, turns the other; either pump will bolt up to your engine. The impellers in the two pumps are different, to accommodate the direction the pump was designed to turn. The mechanical fans for the "V-belt" engines are also different. Insure your water pump is intended for a serpentine belt application.

ET, you and the dealer were discussing apples and oranges!! He's right about reverse flow cooling--different engine! What people here are telling you is a water pump listed for an early block that used V-belts turns in one direction, while the water pump for a serpentine belt, turns the other; either pump will bolt up to your engine. The impellers in the two pumps are different, to accommodate the direction the pump was designed to turn. The mechanical fans for the "V-belt" engines are also different. Insure your water pump is intended for a serpentine belt application.


SHEESH!..thanks for spelling it out!...sometimes I think I'm really 'thick' when I'm frustrated...I get it. I'll be going by the parts store on the way home today from work!
RE: my fan's CFM...[from memory], I believe its a perma-cool...I bought the largest [physically] fan to cover the most of my Griffin radiator as possible, while gaining the most CFM. As I recall [it's been a couple years], there WAS a trade-off b/n CFM and size...none of the dual fan setups would physically fit. And, speaking of fitting; I have the motor positioned as far back against the firewall as possible, while still being able to remove the distributor cap [and it's still a pain], and I STILL only have, [and this is NOT an exaggeration] only a 1/4" between the end of the pulley and the rear of the electric fan! And the fan is as 'skinny' as they MAKE!!! I'm not sure a regular [clutched] fan would even FIT!
However, this will [hopefully] all be a mute point once I swap out the pump...You'll prolly hear me yelling on the West Coast when this is solved! Not only that, but my WIFE will be happy and we ALL know what happens then! :)

Sounds like good advice. However didnt you go down this path already? Did you ever switch in another water pump? If it were me I would move the tranny cooler far away from the radiator or at the very least plumb it seperately. Just a guess since that was an issue with my rig.

Go to AZ ask to see a water pump for a 94 chevy with a 350 then ask to see one for a 80s 350. you will see the difference. This may or may not slove your problem.

Who did your motor work? The intake gaskets can be swapped side to side which closes off a cooling port to one cylinder on each side. this causes these 2 cyl to over heat and force steam into the cooling jacket and the whole thing overheats. It is a ton of work but I done 2 like this from guys who bought long blocks and did the swap themselves. They had very similar symptoms. I would still chase the serp water pump thing first though.

wayne

SHEESH!..thanks for spelling it out!...sometimes I think I'm really 'thick' when I'm frustrated...I get it. I'll be going by the parts store on the way home today from work!
RE: my fan's CFM...[from memory], I believe its a perma-cool...I bought the largest [physically] fan to cover the most of my Griffin radiator as possible, while gaining the most CFM. As I recall [it's been a couple years], there WAS a trade-off b/n CFM and size...none of the dual fan setups would physically fit. And, speaking of fitting; I have the motor positioned as far back against the firewall as possible, while still being able to remove the distributor cap [and it's still a pain], and I STILL only have, [and this is NOT an exaggeration] only a 1/4" between the end of the pulley and the rear of the electric fan! And the fan is as 'skinny' as they MAKE!!! I'm not sure a regular [clutched] fan would even FIT!
However, this will [hopefully] all be a mute point once I swap out the pump...You'll prolly hear me yelling on the West Coast when this is solved! Not only that, but my WIFE will be happy and we ALL know what happens then! :)

I think my Perma Cool was rated at 2950CFM, but it also didn't have a shroud, which makes a big difference in overall cooling efficiency. It would keep the motor cool while driving on the road and sitting at idle, but when in 4-Lo and romping around, the temp would just start climbing.
I had to move my radiator and grill forward in order to clear the mech fan. My radiator is a 3 core brass jeep/chevy conversion, so you're aluminum radiator may be thicker and take up more space.

Yeah, hopefully the water pump will solve all your problems, and you may never have any more issues with heat. Just keep the elec. fan in mind later on as a culprit (especially if not shrouded) if you have any more issues after the right water pump is installed.

and i was thinking about doing a 350 swap.... the starting issues that my 258 is having make me real made but after reading this it doesnt seem so bad.

Again, THANKS for the many ideas and suggestions...I can't wait to get off work today...
I had a buddy 'chide' me today for not coming to 'Pirate' first...actually I did; but only to search, not to post. It's nice to have guys who understand the obsession! :) ...something hard to remember when sitting alone in a garage and yet [another] "Spring" is passing you by...

and i was thinking about doing a 350 swap.... the starting issues that my 258 is having make me real made but after reading this it doesnt seem so bad.

Dude, the engine swap is the EASIEST part of the whole deal! Truly it is a no brainer...it's all the rest that consumes your time. Everything is custom and must be fabricated....learn to weld if you don't already know how; otherwise forget it.

If I had to do it all over again...I'd install a Buick V-6; & use 'built' D44's front and rear on 36's. That rig will do 90% of what mine can do...get better gas mileage...and be ready to wheel in a MONTH!

bubba jeep told ya right reverse rotation not reverse flow.... it'll still pump water but very poorly and will cavitate..... also don't assume that serpentine is always reverse rotation. ribbed w/p pulley is standard and your smooth w/p pulley is reverse rotation.

bubba jeep told ya right reverse rotation not reverse flow.... it'll still pump water but very poorly and will cavitate..... also don't assume that serpentine is always reverse rotation. ribbed w/p pulley is standard and your smooth w/p pulley is reverse rotation.

I'll be damned!...never noticed the difference...God takes care of fools and [obviously] Jeep fabricators. Thanks for bringing the difference to my attention! After reading this, I sat and shook my head...and wondered how many OTHER things I've screwed up because I didn't PAY ATTENTION. [Geez, I sound like my Dad!]

I had a buddy 'chide' me today for not coming to 'Pirate' first...actually I did; but only to search, not to post.

This site is full of folks that have made every possible mistake. Learn from the mistakes and trials of others...its cheaper!

I have not come across a problem yet that the kind, understanding and tender hearted folks at Pirate didnt have an answer for! :grinpimp:

I am running into similar problems with my cj. It has a 350 and i am running a tauras fan. It runs fine on the trail, but too warm going down the road. I am going to try removing some of my inner fenders to let air out of the engine compartment. I will let you know this weekend about the results.

matt

I'm running a reverse rotation on my 5.7. Pick up a h20 pump from a 99 suburban and a fan from either a 4.3 or 5.7 truck. The 5.7 fan will be a larger blade but I'm running the 4.3 fan in my 5.7 YJ and it cools just fine.

I have a 15" high cfm pusher and smaller cfm puller electric fans on my Gen III conversion on a CJ.
Puller is not always enough, so sometimes I need to also use the pusher fan (from BMW E36 air conditioning) to cool it down.

The "REVERSE" spin, regular flow direction water pump did the trick! ...WoW! soooo much aggravation...over something so simple...but that's always the way it IS; right?

http://img523.imageshack.us/img523/5762/waterpumprotationschemagw6.th.jpg (http://img523.imageshack.us/my.php?image=waterpumprotationschemagw6.jpg)

I've posted a pic of the installation directions that came with the pump...even the guy at NAPA had never heard of what I described to him...

Although it is cool today in Atlanta...the difference is immediate...I'm running around at only 165 degrees!...I can't wait for a hot day.

Once again "Pirate4x4" comes through with the answer when no one else could!:D The right-hand image is the one that looks like MY setup.

Later,