So frustrated!
Your also gonna run a little hotter with the iron block now right? About how much of a increase is that supposed to be?
Can some members with iron blocks tell us what your average temp is while driving around please so we can get a better idea?
So I started her up and was letting it idle in the driveway while adding the water wetter to the radiator. The system was pretty full, so I was only able to put half the bottle of WW in. The whole time in my driveway (about 27 minutes of idling), it never even got above 178. So I put the cap on and shut the hood and went inside and got my wallet to go for a spin. When I got back out to the car, JUST from putting the cap on, it had got to 185, and it steadily climbed just as I was making my way out of the neighborhood. By the time I got to the main street, it was already at 200. I thought that was interesting that when I pressurized the system, the temp went up like that. That kinda makes me think that perhaps the stock cap could be playing a role in it.
Alright, so I pulled out of the neighborhood and turned on the axillary fans and drove it around town for about 5 or 6 miles pretty rigorously. The temp climbed to about 217, and then creeped to about 221, but didnt go any higher. The WW looked as if it was working. (For reference, I am running probably 40% antifreeze/ 60% water). I then got to a 3 or 4 mile stretch of backroad where I decided to just cruise along at 55mph. There were no stop signs or anything, so no stopping or accelerating. The temp started going down, and by the time I got to a stop sign, it had subsided to 204. So I start driving it towards the highway for some 70mph cruising. I figured that would be a good test to see if I was getting sufficient airflow through the FMIC (altho, it seemed to me that I was since the 55mph stretch moved the temps down substantially).
I got onto the highway and then cruised north for about 10 miles at a constant 70mph with the cruise control set. The temp steadily kept going down til it was at 199. I then decided to turn around since I was getting kind of far and continue my test going back south towards my house instead of away from it. So I turned around, and then got back up to 70mph (just going easy- part throttle ~30-40%). The temp climbed to 204 by the time I was at 70mph, but then it slowly started going back down and it got to 199 again.
At that point, I figured I would turn the extra fans off and see if they were making any difference on the highway. I didn’t expect them to be doing much at 70mph, but why not.. So I flipped the switch off, and to my surprise, the temp started to creep up. It got to 209, then just kept on going and going and going.. It got to 220, and by that time, I was 10 miles away from my house in the other direction, so I exited the highway and turned back around again heading north. By the time I got to 70mph again, the temp had climbed to 233. I had suspicion that something was definitely up. Theres no way I should be at that temp on the highway with the 16” fan pulling air. I held out until it got to 237, then I went ahead and turned back on the extra fans to get it under control. So after about 20 miles this time going north, the temp had gone down to 222. I turned around and the temp climbed to 226, but then started going back down.
I finally got back around to the exit of the highway to go to my house, and as I had cruised up to the stop sign at the end of the exit ramp, it was at 213. I couldn’t get it to go back to 199 on the highway though, so by this time, I knew something was up for sure. I putted along back to my house, and the temp just kept climbing and climbing. When I finally made it into my driveway, the temp was at 247!
I let it idle for a minute to see if it would help, but it shot up to 251, and I immediately shut the engine off.Ok, so I turned the key back on, and turned my switch off for the aux fans to see if the main 16” fan was working. Just as I suspected, it wasn’t. I do know for a fact it was working when I left my house because I could feel it blowing, and it was keeping the temps in check idling in my driveway before I turned my aux fans on when I went for my drive. So I check the main big 40 amp fuse for the fans and sure enough, its busted
Ok, paperclip to the rescue for a quick temporary fix. But the fan still didn’t kick back on. At that point, I was starting to think that I had blown the fan motor.Just for a little (more) background info, my ATI 16” fan motor gave up the ghost last thanksgiving when I was out of town and I drove the car back home with it running in the 230’s on the highway. This was with the stock radiator at the time. I replaced the waterpump, thermostat, radiator, 16” fan, and added the additional 7” fan at that time. The very day I got her back up and running from all that is when the intake manifold blew up. So this whole cooling system is pretty much all new.
ANYWAY! I thought I had ruined ANOTHER fan somehow since switching around relays didn’t turn the fan back on either. Ok, so I’m wondering right now if I have a wiring issue. Blowing a 40 amp fuse has to mean something is not right. (BTW, I blew 2 40A fuses when my ATI 16” fan crapped out on me). I started thinking of how I had the fan wired up. I have it wired with the ground from the #2 fan and the positive from BOTH #1 and #2 fans spliced together to the positive side of the 16” fan. I figured maybe that’s my problem. I cut the + wire coming from the #2 fan, so now its just got one + coming from the #1 fan relay. Turned the key on and got no voltage from the plug. At that point, I was VERY worried. So I actually turned the engine on and went back under the car to check it, and sure enough, its getting 13.9V. So I plug the fan in, and it starts blowing. The temp resided back to 190 idling in my driveway with all 3 fans on.
Alright, so things learned:
1) pressurizing the system makes the temp go up (does that mean I need a new cap? Or does it mean I've got air pockets STILL somewhere in the system?)
2) The extra fans DO help, but they are NOT sufficient enough to stop it from overheating if the main fan is not working- at least on the city streets, they will suffice on the highway, but thats it.
3) I have a horrible OIL leak somewhere! It must have leaked 1/4 of a quart from sitting in my driveway after I got back from testing. I think I know what it is though. When I was putting everything back together, I remember tightening my oil pressure sensor hand tight, but I don’t recall ever using a wrench on it.. I'm HOPING that’s all it is. And since I have to take the intake manifold off anyways to diagnose the knock sensors, that’s not a big deal to do while I’m at it under there.
4) Maybe my old wiring was putting too much stress on the electrical system. I’m hoping that the way I have it wired now works. If it doesn’t, I’m gonna just hook up the main 16” fan to its own designated relay, and it will be on at all times. I don’t think I need to worry about the system being too cold, and it would definitely eliminate anymore headaches and wondering about the stock wiring.
5) I typed entirely WAYYYYY too much in this post.
please forgive me
Last edited by ChevyChad; Sep 3, 2009 at 10:08 PM.
The Best V8 Stories One Small Block at Time
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the airdam isnt angled enough to make the air all of a sudden turn at a right angle and go up through the intercooler. if your airdam was twice as low and swooped more forward, it might work better.
second- the air that does make it through the IC will be hotter and the flow will be turbulent. then it hits your aluminum shroud and turns again into the radiator. also keep in mind that the more fans sitting on the radiator, the less surface area you have. honeslty i think all your issues are from the intercooler placement. i wish i could explain all that better, i dont know how to type all that so it makes sense :/
I understand your concern. Believe me, I've wondered that myself. However, go back and read post#48 in this thread. At highway speeds (with the fans on) The ECTs are NOT a problem. That in itself right there tells me the air dam provides enough air to get into the cavity above the IC and be sucked in through the radiator.
Yes, it will definitely be warmer than ambient air since it has had to go through the IC, but I really don't think that is my main problem. I am not the first one to do a horizontal FMIC. I've seen it done a few times, and to the best of my knowledge, none of the other guys had ECT issues.
I was looking at it when the car was off, and it was wide open. I am pretty sure that is because I was lazy when I repainted it this time around, and I didnt take it apart, so some paint must have got in there on the stem of the valve and clogged the orface up
So I get to look forward to fixing that too! I swear, it never ends
IIRC, the orifice in front of a H/E should be 3/4th of area of the H/E itself, it should actually be smaller than the H/E. Conterintuative I know. It should also be 6-8 inches away from the H/E to allow the space between to act as a volute. There's some good books about how to maximize air-flow around H/E.
I would suggest taking the license plate cover off and and open that flap, run it around like you just did, with and without fans and see what happens.
And Chad I believe it's perfectly normal for the system to increase heat with the cap on. If you think about it with the cap off it's allowing heat to exit the neck along with steam. Once you cap that it's trapped inside to circulate the system, so technically it should build some heat. I know with my car by the time I'm a few miles from my house it's up to 204*. I never see sub 200* temps at any point after I start driving. My temps usually climb up to 206-208* in slow stop & go traffic.
IIRC, the orifice in front of a H/E should be 3/4th of area of the H/E itself, it should actually be smaller than the H/E. Conterintuative I know. It should also be 6-8 inches away from the H/E to allow the space between to act as a volute. There's some good books about how to maximize air-flow around H/E.
I would suggest taking the license plate cover off and and open that flap, run it around like you just did, with and without fans and see what happens.
I do think opening up the front "tunnel" behind my license plate filler panel would indeed be a good test. I'll have to modify the shroud though because I never did get around to doing that part when I put the shroud together. So that idea never made it past mock-up. It will definitely be done now though.

http://www.gbodyparts.com/product_in...9c405b1e4c488b
I'm not sure if they will fit or not, but its just a suggestion from my previous experience using them.





