I think it's the water pump, but I need to be sure. Since I have AC in the car now, pulling the water pump will be a chore. (Pulling the thermostat even, has become harder than it should be) And I think I'll crap a diamond if I go through all that today and the damn cooling problem's not solved. Here's why I think it's the water pump. It's running hot even with the AC off, and hotter of course with it on. Say 220 max without AC, 230 with it. And that's on the highway. It's cooler at low speeds, but still hotter than it should be. 200-210 without AC in town, and 215-220 with it. I would just blame the condenser blocking the radiator, but it has been doing this since before the AC install. It didn't matter then though, because it only happens on hot days (like now) and it never got over 220, which isn't really all that bad. The most compelling reason to say it's the water pump is simply that it's hotter when I'm doing 70 and cooler when I'm doing 30. And I've ruled some other things out. At first I suspected the thermostat, but It's not that. I took it out, boiled it on the stove and saw it open. Then I ran the car with no thermostat, and it did the same thing. It's not the radiator cap, bought one yesterday. It's not air bubbles in the engine, I burped it, flushed it, more than once. I'm not leaking coolant. It's not the fan, and the fan shouldn't matter at 70 mph anyway. Even if I had big gaps all around the radiator, that should be enough wind to do something. It's not the wrong antifreeze to water ratio. It's not the radiator - at least, I think it's not. I have a big fat Jeg's aluminum radiator. It has no holes, and I just can't see how in the world a radiator with two wide rows of tubes could become clogged enough to cause this. If that happened, I would expect to find sludge and/or debris in it, and I haven't. It used to cool just fine, and I haven 't changed the carb tuning or the ignition timing since then. I don't have any symptoms of head gasket failure, no mixing oil and coolant... All things point to the water pump, right? But here's why I have doubts. The water pump is not old. Maybe a year. I didn't get the "optional severe duty" one, it's just the cheap Cardone stock replacement, but is it really such a cheap POS that it's bad in a year? (If I buy a new one today, it's going to be the heavy duty aluminum one.) The pump is not leaking. And, when I pull the radiator cap after draining some fluid, I can see coolant flowing. I don't know how much I should be seeing, but I do see some. I don't see any flow unless it's filled past a certain level, but I assume the pump is not going to suck water unless the impeller is fully immersed. Sorry for the long post, I just want to be sure. I don't want to waste money and time installing a water pump and find out I need a radiator. I checked everything I can think of. Have I missed anything?
the pump just drives the circulation, if it isnt leaking out the hole or making noise then it is doing what it will. you could change it for a higher flow one, but if your problem is at 70 more then i doubt that will fix it because the high flow compensates for lower rpm. your thermostat being completely out would let it flow too fast and not force it to remove enough heat, so be careful with doing that. you have an over 100 amp alt and electric fan and electric small fan on the ac system correct? try disconnecting the belt from the A/C compressor and running around town (sorry you may get warm during this test ;P ) see if that drops the temp. if it does then the compressor pulley clutch majiggy (sorry dont know the exact term for the piece im thinking of) itself may be worn enough that it is causing the engine to work harder spinning it. if that doesnt affect it then there may be a minor ground somewhere causing the alt to work hard all the time forcing the motor to work harder..... just a couple thoughts, but i dont think your water pump is the culprit...
Water pumps don't just gradually go bad. The part of the pump that goes out, causing you to change it is the impeller bearings. To do what you describe, the impeller would be gradually eaten away by corrosion. I've never seen that happen, not even in pumps that have sat for years in a junkyard engine. What pound rating radiator cap do you have on it now? The higher the rating, the better results you'll get usually. If you do replace the pump, specifiy one for a "police/taxi" or HD cooling. These will have a high volume impeller.
Hold a towel in front of the rad. make sure the fan sucking good air thru.since u added the a/c condenser
Unless the impeller is corroding away. I've seen that, but wouldn't expect it on a pump this new. Not to worry, the 'stat is only out for testing. Turning the compressor off and letting the AC clutch just freewheel does have an effect on the temperature. Definitely runs hotter with AC on, but even with it off it runs as much as 220 on the highway, and it did that before I installed the AC. I thought of that, but at speed the fan shouldn't even be a factor, right? This is such a puzzle. My engine is .030 over, so I could see it being a little harder to cool, but that radiator I've got is a beast. It really ought to get the job done. Let's make it simple: Assuming the radiator is ok... It needs two things to function; air flow and water flow. The fan may or may not be up to the task (seems like it was at some point) but it should definitely be getting enough air on the highway, even with a condenser in the way. (Remember, this problem was here before the AC was installed, just wasn't as bad) So if it's not air flow, then water? What can be hindering the water flow besides the water pump? With the thermostat open/gone, it ain't that...
The lower radiator hose might be collapsing, too low of octane gasoline, timing too high, bad temp gauge. I don't think it's the water pump.
I have checked the lower hose, and it's the flex type with ribs, so it's not collapsing. I run 93 octane all the time. Timing hasn't changed since before the problem started, but I will back it off a little and see what happens. Temp gauge is something I've considered, but I haven't verified it. I will get a thermometer today and check that.
ive seen this in a mustang i built. it made 630 hp. on the freeway it would warm up. it had a huge alum. rad. what i ended up doing is blocking off all the holes and gaps around the radiator suport. air will go the path of least resistance and a radiator has pretty good resistance. id sugest geting some duct tape and trying it. aslo the gap between the hood and radiator support can allow alot of air to bypass the radiator. usually a weather striping will seal that off. the other thing i see with your car is the billet grill. it may be blocking to much air into the rad. try taking it off and see if that makes a difference. we have so little room with these cars for a good size radiator we have to maximize every thing to make them work right.
The problem predates the grille. Sealing around the radiator is a good idea though. I don't have the seal that goes between the radiator support and the hood, was going to order one. You say some generic weatherstripping will do the job, though? I'll experiment with that today, on the way to buy my thermometer...
i still think you should take the belt off and run it. the clutch disengages so the compressor is not turning, but the bearings for the "free wheel" action can start to wear. unless your water pump is super cheapy, i have only seen one wear out the impellar before the brass bushing\bearing went out, and it had also eaten up most of the block and freeze plugs with rust because that owner didnt think coolant was important...
Alright... The Plan... 1. I'm going to take the AC belt off. I really doubt that's related because the problem existed before the AC, but, due diligence. Let's rule it out. 2. Parts store. I'll get some weatherstrip and seal the radiator to the support. Even if that's not the problem, I should have done that already anyway. 3. I'll test drive it to Harbor Freight, and get an infrared thermometer to verify the temp on the gauge. 4. Report back. I'm off...
The problem is solved. First correct guess by 9pm tonight gets to choose my next sig quote! (as in, the current one below by Mavaholic) I'll leave it up for at least 5 days, longer if it's truly hysterical. Nothing profane, sexual, political, or otherwise against Stefan's rules...
