Real quick rundown: DD '97 SH w/ 140k; recently did my t-belt, so figured I'd install an electric water pump from Meziere while I was in there to free up some hp. Having done my research and knowing the inherent problems of an ewp on a street machine, I purchased a separate control from Delta Current Control that regulates the voltage to the water pump and radiator fan based on temperature (runs pump & fan at 10% when cold and increases voltage as there is need). Here's the problem I ran into...

Under load, the car was overheating; fine at idle, but as soon as I'd go up hill or be on the freeway for a little while, it would overheat. So I pulled my thermo realizing that was probably the problem, ran the car without it, and presto, the car is running ice cold (I also have a C&R radiator and Samco hoses). So I bought a new Honda thermo, installed, and back to the same problem. My guess is that there is so much cooling happening from the ewp on the top side of the thermo that it is never fully opening, even if the coolant on the other side is scalding hot.

I called Meziere and explained but the only thing they could suggest (and didn't know if it would work) is drilling two small holes in the thermo (which, admittedly, they say to do in the instructions - however, this is to allow flow while the engine is cold and the pump is on so that there is not a ton of backpressure while the thermo is closed that would destroy the pump; since my pump is only running at 10% when the engine is cold, I didn't drill the holes). I just wanted to see what you guys thought before I have to reinstall my thermo again and then possibly take it out AGAIN. Honda antifreeze is $15+ per gallon and I use almost a full gallon every time I have to refill when I open up the thermo housing, let alone the mess it makes It's getting excessively expensive to be doing it a bunch of times... thoughts?

 

What happens if you wire the pump for 100% voltage all the time does it work properly then? Eliminate the controller as a potential culpret.

Drill a couple small holes in the thermostat if that's what the mfg's directions say. You will need some circulation in the system anyway.

If you insist on using über expensive Honda coolant then put a clean container under the engine to catch the coolant as you drain it. If it's clean then there's no reason to throw it away if it's new.

Pirate

 

Or just run it without the thermostat. You might have to reinstall it in the winter though.

 

um, noooo scott.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Apex1972 &raquo;</TD></TR><TR><TD CLASS="quote">Or just run it without the thermostat. You might have to reinstall it in the winter though.</TD></TR></TABLE>

Not a great idea

 

Any pics of the ewp setup or hose routing diagram? I'm curious if it can utilize the oem coolant bypass to the cylinder head without drillig holes to the thermostat.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">put a clean container under the engine to catch the coolant as you drain it. If it's clean then there's no reason to throw it away if it's new.</TD></TR></TABLE>

lol, just thought of that today


JT - the pump is inserted inline on the lower rad hose w/ a block off plate (& idler pulley) where the factory pump was; it sits next to the battery just forward of the distributor.

 

I just went to the site to check out the pump design. http://www.meziere.com/ps-1333-1269-wpk50026.aspx . If you want this pump to operate 100% of the oem way and utilize the existing coolant bypass, all you have to do is to install this pump in the middle of large metal water pipe (instead of the radiator hose) with the flow toward the thermostat housing. Obviously, you need to modify the metal water pipe and connect two length of hoses. You may have to change the fitting on the pump or find a reducer.

Item # 11 in the pic.
http://www.hondaautomotivepart...5.gif

 

Yep, that's the kit. Yeah, that would make sense, just hard to do since the bypass line sits right underneath the IM. I didn't look at it carefully when I had my IM off, but I might be able to squeeze it in somehow close to the factory position which would make the most sense. However, adapting the metal pipe to and from the ewp with a good seal in a small space would be quite the challenge. All this to say it's not going to happen anytime in the near future, so another option would be good...

 

Not a great idea, but I think its a better idea than running the motor hot. But everyone here is a expert in everything, I forgot my bad.Oh here is a better idea, PUT THE STOCK PUMP BACK ON!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Apex1972 &raquo;</TD></TR><TR><TD CLASS="quote">Oh here is a better idea, PUT THE STOCK PUMP BACK ON!!!!</TD></TR></TABLE>

Right, and I should probably go back to stock ride height, put my stock rims back on and delete my mods because they might be causing problems Nothing improves if ideas and technology aren't pushed. I'm going to try drilling the holes and I'll get back to everyone; fair notice that I'm going to be out of the country for almost a month, so it'll be a little while... Thank you to everyone with useful input.

 

Hey man, whatever happened with this issue? I think my stock water pump is leaking so I'm considering going with the EWP...

 

OK - just an opinion - but, I think the ultimate problem is relatively simple. The electric pump is running at a lower pressure. The thermostat adds some back pressure to the pump and it just cannot push enough coolant. By drilling holes in the thermostat, you will slow the warm up time just a bit, but not badly... Maybe a couple minutes, but this should reduce the back pressure. That is why it doesn't overheat when you remove the thermostat.... Just too much drag on the coolant.

 

word of caution, so far having an ewp has been a pita. after talking with several people, it seems the real problem is the suggested install location of the pump, which is between the radiator and thermostat. i also don't know how you could ever get stabilized temps without a thermostat. after i pulled mine out, when i would get on the freeway my car would drop almost completely back to the cold side of the temp WITHOUT THE PUMP EVEN RUNNING. i don't know how these companies have been suggesting this install location without more problems.

since i blew my headgasket in this whole learning process, when i get the money i will be replacing the headgasket and probably doing a valve job on the head while it's out. when the head is out i'm going to change the pump location to where it should be. the plan is to cut open the coolant connecting pipe on the back of the block and splice in the pump, so it will basically be in the exact location in terms of flow as the stock pump. in fact, i will probably end up splicing the pipe in two locations and basically moving the entire pipe next to the firewall instead of up against the block. i'm hoping an additional bonus will be easier access to the intake manifold nuts.

duanes, to answer your comment, an electric pump will far outflow a stock mechanical pump; the reason most people install electric pumps is to keep engine temps down when running crazy boost setups. in my case, i'm running a voltage controller on the pump that is regulated by temp. so when the temp is low, the pump flow is low, and as the car heats up, the pump flows more, which eliminates having to manually switch the pump on and off like many people have commented on before.

so alblude, right now i would definitely say don't do it unless you're in the mood for headaches. i have never heard of anyone having major problems with the stock water pump. if you want to wait a few months, i'm hoping after my tax return to be able to fix everything up and i'll let you know if it works out the way i'm planning.

question: does anyone know which way the coolant flows through the connecting pipe? i'm assuming it travels from the t-stat towards the water pump, and the stock pump pushes it through the block, but just want to be sure i get the flow direction right when i put the pump in.

 

Like I said a few months ago, PUT THE STOCK PUMP ON. OEM FTW again!!!

 

Hey gstrudler,

Thanks for the reply! My problem right now is that I suspect the stock water pump to be leaking (or at least its seal) and so I'd like to sort this out once .

Anyway, I really think that the location of the water pump is not really dictated by the flow, but by the driver of the pump which in our case is the timing belt. Liquid is virtually incompressible so having the pump closer vs. farther from the thermostat would not make a difference on the resistance created by the thermostat. With that said, I'm pretty sure that the 2 holes required to be drilled on the thermostat need to be there relieve pressure on the EWP's motor and make it last longer.

I'll do a bit more research in the mean time ...

 

I do think it matters which side of the t-stat it is on, as one way it is pulling the fluid through and the other way is trying to force it through. With my setup, I wasn't as concerned about motor life as the pump is not being driven 100%, but proportionally to the amount of cooling needed, so when I first installed the ewp, I didn't drill the holes. However, my car kept overheating on the freeway because apparently the thermostat wasn't opening up (verified pump and fan were running, so that wasn't the problem). Drilled the holes, and presto, no overheating. I had it recommended from a couple different people to reroute lines from the t-stat to the pump if I were to keep this configuration as well.

 

So you have it all sorted out now?

My buddy had the same problem - well sort of. He eventually drilled the holes in the expensive Power Enterprise thermostat also.

But he said on the highway that his temps would just drop to bone cold, lol. In cool weather, he would actually put a piece of cardboard in front of his radiator to prevent it from cooling so much.

He never tried a voltage controller, as you have.

 

I had tried running it without the t-stat for a little while, and that's exactly what happened. Even with the voltage controller (running a minimum 10%), my temps would drop almost all the way to the bottom on the freeway. It's been running pretty well for now with holes drilled in the stock t-stat. This is all going to get changed around in a couple months when I rebuild the motor though.

 

i had a similar prob. my car overheats going up hill. and in traffic. just wonder can i drill holes in my low temp. thermostate with stock water pump? thks.