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DIY - Replacing the C5 Water Pump

111K views 120 replies 42 participants last post by  Maniacmechanic1 
#1 · (Edited)
Well folks, you get to benefit from another situation I found myself in. The day before I was supposed to drive to Arkansas from Kentucky, my water pump decides to reveal to me that it was leaking. I had been smelling antifreeze but it wasn't leaving any drops on the floor. Well, that finally changed at the most inopportune time.

Some info on how to check for a leaking water pump. First of all, if you smell antifreeze, you have a leak. Period. You may not see it, see coolant on the ground or be able to locate it but trust me, you have a leak. I think I have managed to have a leak in every possible common location:

  • The "T" connector located on the surge tank (it usually cracks).
  • The upper hose connector at the top of the radiator. It develops a hairline crack. There's a TSB that has you polish it out and not replace the radiator. I replaced my radiator instead because it had over 100,000 miles on it.
  • The water pump.

Here's the deal with detecting a water pump leak on the C5. The fluid will not drop to the floor directly under the water pump unless you have a really heavy leak. It will land on the belt or belt pulley and sling to one side of the car (most likely the driver's side because of the direction that the belt travels). I didn't know that as I kept checking dead center of the engine on the garage floor. My leak was extremely small up until the point that I actually found it. Hey, I'm old school and my previous experience taught me to check dead center of the engine on the garage floor. Now I know better. :lookinup:

This turned out to be a rather easy repair compared to some that I have done. I would easily recommend a shade tree mechanic take this on as long as you have one very important tool: hose clamp pliers. Don't even attempt this repair without them as there are quite a few hose clamps that you have to remove. Those things will take you forever to remove with a pair of pliers. Don't waste your time, buy a nice pair of hose clamp pliers with the extension cable. You'll thank me later. You'll see them in the pictures below.

With all that said, let's get to the repair!

Tools needed:
  • Hose Clamp Pliers
  • 3/8" 10mm Socket and Ratchet
  • 3/8" 15mm Socket
  • Flat Head Screwdriver
  • Dielectric Grease or Vaseline
  • Radiator Hose or White Lithium Grease
  • Safety Glasses
  • Another socket for the thermostat bolts but I forgot what size it was! :lookinup:
  • These instructions! :thumbsup:

This repair should only be done when the engine is cool or cold.


Step 1: Remove the air cleaner intake duct. This is actually done as a unit. You don't have to remove the entire thing as I did, you can just remove the air bridge but for me, it was quicker just to remove the whole thing since I know how. Here it is removed:



To do this, pop up the pins that hold the air bridge onto the radiator shroud.



Unplug the mass airflow (MAF) sensor connector. Once you get it unplugged and the harness is disconnected from the clip that holds the harness down, move it toward the back of the engine out of your way.







Remove the air filter in order to make the next step simpler. As you can see, I'm a firm believer in the K&N filter.



This next part is kind of tricky the first time you do it. The air cleaner intake duct is held onto the front frame cross-member by 2 rubber grommets. The air box just pushes on and pulls off. The first time you do it is like pulling teeth because you really have to give it a tug. It gets easier to do once you've done it before. See pictures below.





You will also need to unplug the Secondary Air Injection (AIR) hose. The bottom part of that hose simply pulls apart from the top part if you twist it back and forth.



Last of all, loosen the screw that holds the air bridge onto the throttle body.



Once you get all this stuff disconnected, separated and unplugged, the air cleaner intake just simply lifts out of the engine bay. Put it to the side.


Step 2: The first thing you need to do here is look at how the accessory belt is routed. Take pictures of it from various angles so that you will have something to look at when it comes time to put it back on. That's what I do before disassembling anything.

Remove the accessory belt from the accessory tensioner pulley and allow it to drop toward the bottom of the engine. There is no need to remove it all the way so don't make more work by doing so. To remove it, use the 15mm socket and rotate the pulley clockwise (toward the driver's side), until you can slip the belt off the tensioner.





Step 3: Drain the cooling system. In order to do this, you will need to raise the car. for those who don't have a lift, here's the way I do it.

A) Drive the front of the car up on some 2X12's.



B) Using a low profile jack that I got from Harbor Freight, I center a 2X4 on the jack plate and run it under the front of the car.







Once in place and lifted, I support the car with jack stands.



I follow the same exact procedure for the rear of the car, making it slightly higher for draining purposes.

Warning: Pay special attention to the front jacks as you raise the rear. They could topple over if you get to extreme with your lift height!!!



Now I have all kinds of room to work under the car. :D



Remove the overflow tank cap and get your safety glasses on. Remember, safety first! :thumbsup:





The actual draining of the system is pretty easy. You simply loosen the drain cock (hey, I didn't name it... that's what it's called) and you will see the fluid begin to flow. You will turn it counter-clockwise. Do not completely remove the drain cock, just loosen it until the antifreeze starts flowing real good. Now go have Dagwood Pizza and your favorite drink because it will take the fluid a little bit to completely drain.. :D





Once all of the coolant has drained, close the drain cock and lower the car. You can reuse your old coolant if you want to but if it wasn't changed recently, I don't know why you would. Don't be a cheap azz, buy some new fluid for your baby. Don't get the 50/50 stuff because you're paying for water, which is free (however, if you don't have access to distilled water, buy the 50/50 stuff). Other than that, buy the full strength stuff and dilute it with distilled water. You can use A 50/50 mixture of clean, drinkable water but use only GM Goodwrench® DEX-COOL® or Havoline® DEX-COOL® silicate-free coolant. It takes approximately 11.9 liters (12.6 quarts) to refill the cooling system.
 
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#2 · (Edited)
(con't)

Step 4: Get out your hose clamp pliers and reposition the inlet and outlet hose clamps at the water pump. See pictures below.












Step 5: Remove the inlet and outlet hoses from the water pump if you haven't already done so.

Step 6: Reposition the heater inlet and surge tank outlet hose clamps at the water pump. See pictures below.








Step 7: Remove the heater inlet and surge tank outlet hoses from the water pump, as per directions in the pics above (if you haven't already done so).

Step 8: In this order, remove the thermostat bolts (2), the accessory tensioner bolts (2) and the water pump bolts (6). One thing that I always do is ensure that I put the bolts I remove back into the exact hole that they came out of, especially when dealing with aluminum engine parts. Call me crazy, I have my reasons. If you want to do that also, make sure you keep track of the bolts as you remove them. Check the picture below.



Step 9: Remove the water pump. Nothing tricky here, just wiggle that chunk of metal out of there. Make sure you remove the water pump gaskets if they don't come off with the old water pump.

Clean up the area where all that Dex-Cool has leaked. You want to be able to detect any new leaks. I used Brakleen from CRC to clean up engine dirt. That stuff is good but you will need about 3 cans. You can go through that stuff pretty fast and it is not exactly cheap.

Now you're ready for the new pump. The new pump comes with the gaskets for the water pump and thermostat. The ones for the water pump are paper, which is NOT what comes stock on your car. Don't use the paper ones that come with the new pump, go buy the original GM gaskets. They only cost me $23, well worth the extra quality. Here's the gaskets and new part numbers as of this posting. You will need 2 gaskets (same part number).





You can use the rubber gasket that comes with the water pump for the thermostat. Just make sure that you replace that t-stat gasket!






New water pump. I paid about $180 at O'Reilly's for a brand spankin' new one.






Now all you have to do is reverse the installation process. Here's the fun hurdle that you will run into. Trying to keep the water pump gaskets in place as you line up the mounting screws and water pump. I could have used some type of grease to make the gasket stick to the motor or the water pump itself but I didn't know what was safe to use ( I didn't want to create any leaking issues). Thus, I spent the next two hours trying to do it without any help. It was a bitch.

Once I got it on, I went in and had another pizza. :smokin:

One helpful tip: Use the dielectric grease or Vaseline on the rubber grommets that attach the air box to the front cross-frame. The grease will make it easier to snap back on. Use some radiator hose or White Lithium grease on the inner lip of the hoses to help ease the installation of them. DON'T use a lot. A teeny, weenie bit goes a long way.


Here are your torque settings for all the bolts.

  • Tighten the water pump bolts a first pass to 15 N·m (11 lb ft). Tighten the water pump bolts a final pass to 30 N·m (22 lb ft).
  • Tighten the accessory drive belt tensioner bolts to 50 N·m (37 lb ft) starting with the lower bolt first.
  • Tighten the water pump inlet bolts (thermostat) to 15 N·m (11 lb ft).

That's it folks. It looks like a complicated job because I'm long winded and took a lot of pictures but it really is an easy fix if you don't know how to work on your Vette. With these instructions, anyone can do it.

Holler if you have any questions! :)


The Junkman
 
#6 ·
Another awesome writeup AJ !! Dayum, I spent so much time looking at, and reading this DIY that I feel like I just changed a WP all while sitting here on my azz with my feet up on the desk !! I need a break dude..... :D

Here's something I never knew existed:
hose clamp pliers

I've always used big lock pliers to remove these style hose clamps.
-Does this tool work well in areas that are space limited ??
-Does Harbor Freight sell this tool ??

Thanks for the great info. I've changed a bunch of C4 WP's, but never a C5. I'm sure the day is approaching though...

(oh, I gotta' ding ya' for putting your MAF and airduct assembly on your roof top !!!! Bad man....Bad man ......bwah hah hah j/k)

:thumbsup:
 
#7 ·
That is my old roof. I have a new one now. :thumbsup: :D

There are 2 types of hose clamp pliers. One has a cable (great for getting into limited space areas), and the kind without the cable (okay for working in open areas). I would only buy the cable type. They are more expensive but they work in both areas really well. More than worth the money, if you have spent time bent over the fender trying to get a pair of pliers to work. All it took was for me to experience that once in a Auto Zone parking lot and never again. :down:

I got mine at Sears for $40.00. They also have the SK brand for $104.00, but you would have to be smoking crack to buy those.
 
#8 ·
Wow, great write up Junkman! I know I'll be needing this one at some point in time. I haven't had to do this yet, but your step by step makes it easy. Thanks.:partyon:
 
#12 ·
Well Done AJ :thumbsup:
Just curious, how does the O'Rileys water pump manufacturer compare to OEM for fit, finish availablity and price? Understand you did this prior to a road trip, how easy was it to locate................in a hurry?

.........and approximately, what mileage were you at when you first noticed you might of had a leak?
 
#17 ·
I started smelling fluid just after 100,000 miles, but it was next to impossible to locate because I didn't realize how the leak was traveling. It was also dry in the engine bay. As far as availability, it's a very common pump. It goes on a very common LS1. I verified the leak at 3:30 PM and had the auto store pull one from their warehouse and send it to the store in one hour. The gasket will take a little longer to find but I lucked up with those also and found them the same day. Price was as I listed in the write-up, and that was for a new one.

Can I offer one thing? If you have the stock style spring clamps PLEASE PLEASE PLEASE replace them when you do this with either new ones or the more prefered wormdrive type. I just about blew the motor in my truck recently when I replaced the radiator and the bottom hose clamp decided to not clamp anymore and the hose came off. They are only a few bucks and don't depend on pressure to stay on the car, they tighten.:thumbsup:


Also the pump replacement in my car with the LS was super easy, I didn't even need to remove the intake:laughing: God love a C4.
That's probably a good idea only I don't know if I would use the traditional kind. During my first slow leak, I bought some of those and the leak got worse (I hated the OEM kind). After I put the OEM type back on, the leak stopped. I then went and bought those hose clamp pliers. :lookinup:
 
#13 ·
Can I offer one thing? If you have the stock style spring clamps PLEASE PLEASE PLEASE replace them when you do this with either new ones or the more prefered wormdrive type. I just about blew the motor in my truck recently when I replaced the radiator and the bottom hose clamp decided to not clamp anymore and the hose came off. They are only a few bucks and don't depend on pressure to stay on the car, they tighten.:thumbsup:


Also the pump replacement in my car with the LS was super easy, I didn't even need to remove the intake:laughing: God love a C4.
 
#22 ·
AJ,

Thanks for taking the time to create and share all of your DIY write ups. As usual it was excellent. :partyon:

Keep up the good work. (I hope you never upgrade to a C6 or C7, I want to keep my C5 for a while !)

Ingey
 
#24 ·
Don't worry, I plan on keeping my C5 until I croak! :thumbsup:

i wish the service manuals i use are as good as your write ups
I do too! :laughing:

I was looking at the manual and it showed a picture of two bolts being removed from the water pump. Then it said remove the pump. I was like, "This damn thing is stuck!" Then I realized that I needed to remove 4 more bolts. The manual didn't say that but my buddy and Master mechanic said that service manuals are not written for people like me. :rolleyes: :laughing:

Damn manuals! :laughing:
 
#28 ·
Benfold

Junkman, thanks for the detailed step by step. My C5 almost overheats and it drives me nuts. Have you heard of anyone with expierience lowering the temp that the fans kick on? Eckler's has a unit advertised that will allow you to adjust the temperature at which the fans engage. Or, how about the Be Cool, double row, aluminum, direct fit radiator? There's also an electric water pump that's advertised to lower the operating temp by as much as 20 degrees. I'm deployed on a Navy destroyer until Mar 2010, but want to stage all my parts before I return to do some mods. Do you have any inputs for the above mentioned items? The C5 runs great, runs cool at speed, but in traffic in Sacramento, OMG. I don't ever want to cook the engine, so I'm trying to find a lasting solution. Any inputs you have are much appreciated.
 
#30 ·
Junkman, thanks for the detailed step by step. My C5 almost overheats and it drives me nuts. Have you heard of anyone with expierience lowering the temp that the fans kick on? Eckler's has a unit advertised that will allow you to adjust the temperature at which the fans engage. Or, how about the Be Cool, double row, aluminum, direct fit radiator? There's also an electric water pump that's advertised to lower the operating temp by as much as 20 degrees. I'm deployed on a Navy destroyer until Mar 2010, but want to stage all my parts before I return to do some mods. Do you have any inputs for the above mentioned items? The C5 runs great, runs cool at speed, but in traffic in Sacramento, OMG. I don't ever want to cook the engine, so I'm trying to find a lasting solution. Any inputs you have are much appreciated.
Sampson, you've been reading too many threads over at CF!

First of all, I need to change your way of thinking about this whole problem. Nothing needs to be reprogrammed. What must happen is you need to address the reason your car is over heating. From the problem you are having, I can already tell that:

  • You car has a lot of miles on it
  • The radiator has either never been cleaned or changed.

The first thing you need to do is look at this thread. This is the no cost first step in diagnosing overheating issues. If this doesn't resolve your issue, then you need to look at one of two things: the thermostat or the radiator itself. I say this assuming that if the water pump was going bad, it would leak (at least everyone that I've had go bad, leaked first). The thermostat is a cheap fix but of the two, it is most likely not the problem. You can go ahead and replace it but DO NOT get anything other than the stock temperature thermostat. So many guys have the misconception that a lower thermostat will make your engine operate at a cooler temperature. People who think this are totally in the dark about how the cooling system works on a car.

If the thermostat doesn't resolve your issue, then you are looking at a new radiator. I paid $190 for a brand new aluminum radiator for my C5 so the cost is not an issue if you were thinking about going the BeCool route. Talk about overkill, the only reason you need to look in that direction is if you have heavily modified your engine and are producing way more heat than stock.

You and I both have read a lot of threads on overheating issues all over the various Corvette forums. Here's what so many people fail to realize until you bring it up. If the car never had a overheating issue when it was new, then it must have obviously been designed with a effective cooling system. If the initial design was more than effective (and it was, no matter where you lived), then there is no need to re-engineer it if your engine is stock. You will hear guys say that once they changed their radiator to a BeCool or other high performance brand, their overheating issues went away. You know why? BECAUSE THEIR ORIGINAL RADIATOR WAS BAD TO BEGIN WITH! Had they replaced their radiator with a stock OEM one, their overheating issues would have still went away because they addressed the problem!

Remember this rule: Don't re-engineer the engine, address the problem. If you address the problem, the issue will eliminate itself. There are a lot of GM engineering wanna-be's out there posting on the various forums (especially CF). Don't let them suck you down to their level with an engine that has been designed by guys who actually know what they are doing. If these wanna-be's actually did know what they were talking about, their paychecks would have a GM logo on it and be in the 6-figure a year range.

Let me know if I am correct about your car and we'll take it from there. :thumbsup:


I have not called it that since I was in the Navy back in the late 60's. Once a Marine always a Marine, and I respect you for that.
Again great write up and I look forward to your window leak fix.

:thumbsup:
Damn, now you're giving me work! :laughing:
 
#31 ·
Junkman, Roger,
I've always been clear on the t-stat, I know that's not the problem. Yes, the car has 135,000 miles on it. The radiator was replaced in July 09, I paid like $230 for a new one, and had it installed by Corvette Shop in San Diego. My old one was leaking, plastic end tank had a crack. I will read the thread you sent me. The condenser, is that for the AirCON? It seems the guy would have cleaned it when replacing the radiator, buy perhaps not. It's true, I don't care about spending $700 for a BeCool, if that would fix it. I know that if the operating temp gets to 228, the fans come on, and it cools to 215 or so if still in traffic. The problem usually surfaces after I get home, and shut the car off, it spews out of the top of the coollant tank. I've never seen it go beyond 232, but I don't like to see it that hot. I do understand that it was designed to work correctly, and that the design engineers know what they are doing. I can't find any other evidence that it's leaking, or water in the oil, anything like that. I thank you for your inputs. Unfortunately, I can't even look at it until I return from the Persian Gulf in March 2010. Could it even be something as simple as the Cap on the Coolant tank? (You old Devil Dog) (Last year, we deployed with USS Peleliu (LHA 5), lots of Marines on that thing. :thumbsup:
 
#32 ·
DAMN! They're still using that bucket of bolts? :laughing:

I sailed with the Peleliu in 1985! I was on the USS Ogden (LPD-5). We also had the USS Cayuga LST-1186 along too! That puppy was in the movie "Airport 77"! Damn, what a small world! :thumbsup:

Back to your car, it could be something like the wrong mixture of antifreeze. There is still the thermostat to look at so we'll have to address it when you get back. You've knocked out the hardest job (the radiator), so now you only have the easy things left. My first SWAG is the thermostat.

Yes, the condenser is for the AirCON. It also needs to be cleaned. That is another thing to check. As far as how the fans work, here's the deal:

The low speed cooling fan is commanded on when the coolant temperature reaches 108°C (226°F). It is turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fan is commanded on when the coolant temperature reaches 113°C (235°F). It is turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

Definitely look me up when you get state side. I look forward to the chat. :thumbsup: :thumbsup:
 
#54 ·
Junkman thanks for the info, I have a 99 convertilbe and I'm sure somewhere down the road I will be needing this info. I also like the way you supported your corvette on the jack stands, I'll try that next time I work on my corvette.
First off, welcome to DC! :buhbye:

There are a whole lot more write-ups here that I and others have done. Look around and check the place out. I'm sure you'll find that it is different from other forums that you may have visited. :thumbsup:
 
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