Hey guys, I bought an '05 SRT6 today with 26K miles. Traded in my 05 Mustang GT. Wow the srt6 is exactly what I wanted!

Anyways, I read alot on everyone's dead intercooler pumps. I was thinking of buying the LET water pump from their site, $150. Do you think I should just do it and replace it for a piece of mind or wait it out and hope for the best?

I want to keep my new baby running for a long time

 

with 26k it might have been changed already or never had a problem because it was actually driven. I didn't have any issues with mine but put a ford lighting pump anyways. Usually around 80 bucks on ebay and you can pick up the plug for like $10. Some over on mbworld just posted the part number for the plug. I got a used plug from a ford mechanic, he had it lying around. Unless your opting for the bigger intercooler not sure the johnson pump will make a difference.

 

Actually if you want to skip the inevitable repair go ahead and order it.
I have found it's much easier to change at home or in your own shop than when it goes out on the road when you least expect it.
I am not sure what Cruzin meant by his remark that with out the larger intercooler it wont make a difference? The size of the heat exchanger has no barring on whether or not the pump will go out or not?
There is no question that the "Johnson" pump is far better than the stock M/B pump.
Enjoy the Ride...
Mike

 

I've got 22K on mine now, and when the pump arrives, I am going ahead and changing it....no use waiting for the old one to go...it would be my luck it would go on my way to WWDC....

 

I ordered the Johnson pump from LET last week and will install it when it arrives. I want max coolant flow and I am planning on seperating the IC system from the radiator system. The Johnsom pump gives higher flow rate.

MikeR

 

The flow isn't the problem, it's when the pump stops working that's the problem. Your car will still cross state lines. It's not like it's going to shut off and die. You will have warning signs. Any pump you change to will not run the car any better. If you increase the pump too much you will actually run the flow too fast and have an adverse affect. If you had the larger ic than the increased flow of a johnson would bring you back to normal. Otherwise the stock flow is fine, just the pump motor is what is the problem. That clear it up? Will the johnson pump last longer? No one knows. Has anyone left one sitting in the sun for 2 years then installed it to see how long it works? Montana is inferring the johnson is a better product, it may be. No one has had one on long enough to prove otherwise. It's up to you, if you are leaving your car stock and don't want to splice any wires or hoses, brackets, clamps then just replace with a stock one or see how long it lasts.

 

cruzinquick, you have made a statement that I have thought of all along on the "Johnson Pump". The OEM pump flows 4.X GPM and the Johnson Pump flows 7.X GPM, thats almost double. There is a point that the coolant can flow to fast through the heat exchanger that it will not get the full cooling effect. I may be wrong, but when the German engineers designed the I/C cooling system on these cars you would think the 4.X GPM was what was required to cool the system at it's best. I just went through a similar deal with my old 64.5 Mustang, I had installed 3:55 gears in the rear end and started having trouble with the car over heating at highway speeds. At first I thought it was sucking (collapsing) a radiator hose shut, but after trying different thermostats, better hose's and radiator caps. I came to the conclusion that it was pumping the coolant through the radiator so fast it was not cooling the coolant. I changed the rear end to a 3:25 gear and no more over heating at highway speeds. I myself for now will stick with the OEM pump till she goes out, then make the choice of what I'll do.

 

So are you guys saying you think the air temps will actually be hurt by a faster flowing pump? I mean I understand what you're saying, I've dealt with the same reasoning when it comes to computer cooling, but do you think in this specific case that will happen? I dont want to install something that may hurt cooling since the stock one is working for now.

Stop making me cry

 

I'm no expert on how fast coolant should flow through any type of heat exchanger, I was just speaking from personal experience on the Mustang. And I might add that at the US 41 track event there were 3 SRT 6's I believe I was the only one with a stock I/C pump, stock heat exchanger and just a "SL55 -Y" instead of one big 3" intake. And I think I had the fastest SRT 6 there. Anybody that was there correct me if I'm wrong, because I do not like making false statments.

 

I have to get into this one, for what it is worth.

I don’t believe that the flow rate will adversely reduce the cooling of the motor or SC. More is better as the whole heat exchanger surface is then the same temp (almost) and gives the most rejection of heat overall for a given heat exchanger “H/E”.

Think about it, if there is a 1 or 100 degree difference between the motor and water on one side and between the water and the air on the other side, the faster the flow, the more material is run past the surfaces (liquid side of the interface) and the greater the differential, i.e. the radiator is held at a more similar temp top to bottom and the motor on the other side is experiencing a more similar temp on the cooling side, the greater the amount of heat moved into and out of the water / mixture.

I have been off the air for several reasons, but was going to publish some rather shocking findings about the SRT-6 cooling system as it relates to the supercharger. The problem[s] aint what you think, but that is for the next article.

First and foremost, the Johnson pump in a SRT MINE with the LET heat exchanger runs about 3.5 to 3.7 GPM.. I know this as I added a flow meter to see what the heck I was fighting in my car. I cannot get but 3 to 7 degrees delta in to out on the intercooler and the LET radiator assy. I have added baffles, ducted more air, induced the main fan motor / computer to run at a higher rate (speed), and tried taping off all air leaks that might allow air to bypass the H/E as it is called in the forum. My measurements are for a 55% antifreeze/distilled water mixture cold and hot motor conditions. I added a relay to command the pump and 4 fans that I put on the H/E, so that I can monitor the temps with and without pump operation…I have also flushed the 14,000 mile old system twice with radiator cleaner to be sure there is no gunk on the passages internally -motor and radiator.



At 3.7 GPM and assuming 8# / Gallon, about 6 degrees delta is only a lousy 177 Btu per minute extraction, and that is not enough for me. I have ordered a new heat exchanger to put this problem to rest, as it has about 280 inches of face or surface to reject heat. LET is about 5” by 20” and in my estimation too thick to allow sufficient airflow as it is installed. When I have RESULTS I will post them to show if I have anything worth the ‘paper’ it is written on.



The H/E and S/C water that I have been measuring ( with a differential digital monitor with plug in probes ) has been running between 120-135 degrees in the intercooler loop and that is against an 85 – 95 degree ambient. That should (I would expect, and won’t stop till I get there) allow the intercooler water LOOP to be more like about 105 - 115 degrees with a typical 20-degree differential (loss) across the intercooler and H/E interfaces.



If you were to allow the water to move slower (try to figure the rate it moves now in foot/second on a 3/4" hose, a good assignment for Brian} and allow it to get HOTTER, first the S/C is not cooled as much [That would be a bad thing] and second the H/E is not doing as much for the last part of the H/E core is much cooler than the first part. You would be wasting the H/E's capacity!



I had a customer who wanted me to help him maximize the heat that his wood stove delivered to his house? He was a bit of a geek, as he wanted to formulate an algorithm to operate a fan that would blow the air through his stove. Seems that he thought that the computer was needed to do this.



My answer was that the fan should run all the time as if there was heat in the stove he should blow the air to help SCRUB the heat exchanger surface as much as possible to cool it in an attempt to extract the Maximum heat in the stove. He thought about it and decided that this approach would do what he wanted with less hardware, durn it. The goal was to extract the max energy out of the system, and regulation of the home temp did not figure into his request.



Ill get to a bit more experimentation so that I can get the heat issue before the Forum.



P.S. I now have my thermometer gauge running at 2 clicks up on the dial with my 172-degree stat without additional fans or gimmicks. Stock is 3 clicks or mid scale, TA DAA



Further, I also still do not fully believe that the pumps are failing as often reported. To that end I still offer postage to anyone with a “dead stock pump” so I can do a ‘post-mortem on it, or them; ( as in several pumps - not the other forum members. I sorta know how you "guys" are/think )


ENJOY, WOODY

 

Woody,

I am waiting for a LET exchanger, johnson pump, and intake spacers from "the toy" and wanted to change them at the end of my warranty. I have had the pump replaced to correct the typical issue but didn't think about getting the old pump for the PM. Sorry just wasn't thinking CSI at the time. If these new additions are not going to gain me anything such as performance, longevity, etc. I may just forget about it. I eagerly await the publishing of youre research.

 

Depends on what's your interpretation of performance? Our cars suck in the heat. The only way to trick our cars to run just as well in hot weather is to introduce something nice and cold like methanol or alcohol in to the intake. Ok nitrous does the same with bonuses. Off topic though. My point is once the car begins to reach operating temps performance peaks. What Waldig is trying to accomplish since he autocross races is keep those temps down to keep optimal power for as long as possible. In drag racing we only need it for a few minutes if that. We never need the extra cooling unless your street racing or highway racing. Is normal cooling good enough? I would say yes, because not one person regardless of how hot it is has ever complained of overheating. Even running at the track for 20 runs. So upgrade the cooling to keep your "performance" peak longer. Not going to improve your quarter mile time, but should improve your lap time in autocross. What you think professor W.?

 

Ahhhhh...another former Mustang owner sees the light !
Welcome!
Frankly, since your car is still under warranty & IMO, if it goes bad get the Bosch replaced under warranty. Why blow $125 of your own hard-earned cash? If you feel insecure about the pump after the warranty expires go & buy the Johnson & keep it handy, just in case!

 

LOL, yup another Mustang owner. The thing about the Mustang is its a defining point in a person's automotive life. It helps them realize if their into raw tire spinning rumbling performance, or if they're more into all-around performance cars that have great speed, handling, and a hint of luxury. Thats why many Mustang owners either move onto the Corvette or leave the scene completely for smaller and more well-rounded sports cars. That would be the class I fall into....

Anyways, I went ahead and ordered the pump. I'm the kind of person that prefers to feel comfortable rather than save money. Installing it will help me gain some confidence with this car because after looking under the hood I"m afraid to even touch it. Its not 'dumb' and self-explanatory like the Mustang is. Its almost intimidating. Its my first forced-induction too, a whole new world.

 

Mine failed- actually was bad when I purchased the car.
I bought the Ford Lightning pump for a replacement. Doing so I was required to replace the cover with the hose ends on it.
Upon removing the cover it was obvious where the failure occurred. The cup shaped magnet was cracked -and broke in a few pieces.
I believe this is the weak point.
Here it is: (as you can see -the crack looks like it was there for quite some time, rusty, not a fresh break)
Pump3.jpg

Personally I would not change it till it fails - there are no guarantees.

 

BOY WOODY, THAT WAS A MOUTH FULL .

Punkin this is a little off the subject of the I/C pump, but one reason I did not choose to get a larger heat exchanger is because they were thicker and I didn't think they could be much taller than the OEM. That being said you are not going to increase the surface area for air to flow through. I have never seen how close the larger heat exchanger's sit's to the A/C condencer, but I know the OEM sit's 1&1/4 inch away from it. I'm just guessing, but I believe it was designed that way so air can flow through it. If the larger/thicker heat exchanger is sitting pretty well against the A/C condencer that would prevent air from flowing through it. I agree with cruzinquick, I would think the larger heat exchanger would not help much in daily driving or drag racing. I moved my OEM heat exchanger forward enough to install a couple cooling fans to try to make it possable to control my I/C coolant temp's to make more consistant runs in drag racing. I also have a digital temp gauge with the sending unit mounted in the heat exchanger, AMGJerry rode with me down the track a couple times with a data logger plugged in and said my gauge was the same reading as the I/C coolant was on the data logger.

 

Well, thanks guys...I will just "hang my johnson" on the wall until I need to use it........

 

That works too, but I was thinking if a pump were dieing you wouldn't know it until right before it died... Which means youll have hotter air and possibly degraded performance for awhile before the pump finally goes completely.

True? no? If you say not true, then ill save mine for when its needed too....

 

Woody, I don't want to question your knowledge. But here are the spec's of the Johnson Pumps. I don't get where you are getting 3.5 to 3.7 GPM. And I believe most people are running the 10-24504-03 CM30P7-1.

 

My personal experience with the pump was it did give me notice before it failed. For several days (4-5) before complete failure, I felt a slight sluggishness and the power surge. All was ok until sometime later when it would do it again. Knowing (at least thinking I knew) what the problem was and also knowing my dealership, I figured I needed to get the unit to fail completely or the dealer would never fix it. As it was, it took the normal 3 visits and me pleading with them to please "check or look at" the pump before they finally did. There must be a flow chart that is used and the pump seems to be way down the list.

Good luck