raggy 00

when i got my car back from the guy doing the performance mods, i noticed the blower didnt seem to blow any force of volume.... i asked the vendor and he said he didnt touch any of the duct work... but he did take the console apart... that was last fall... i lived with the weak blower, till this summer and I took the car to my local repair shop, thinking he could replace the blower or the switch. he says they both are working fine... he said its probably a vacum issue and the louvers in the duct work and not being controlled and maybe they are all wide open... he says it is probably because of the new cams Long duration... and thats killing my motors vaccum. So my question is: is that possible? is that a valid statemtn that large duration cams can effect the vacum... and if so, what path is the solution? i know on those really hot days, i can drive from stop sign to stop sign with the AC on, or the car overheats...... but I can get on the highway and if i maintain 45 mph or more, i get enough cooling to run the AC and stay under 210 degrees... thanks Bob

redzg

Much more likely that the vacuum line is not connected to the back of the intake manifold, and now the mode valves aren't working. Check if there is air coming out of the defroster vents with the mode set for dash. Lunch at Tortas El Ray says it is...

Vetteman Jack

Moved to C5 Tech.

raggy 00

the air does come out everywhere...no matter what selection is used...... ill look to see if there is a missing hose connection..... but since the mechanic knew it was vacum related.... i would think he would have looked for the dissconected hose!!!!!

redzg

The fitting at the back of the manifold is rubber, feeding into a small diameter hard plastic line that runs over and down the firewall and into the cabin behind the battery. Very, very common for the plastic line to break in that behind the battery area. And oh so much fun to find and fix.

raggy 00

I found an article by a guy who said it might be because the engine mod shop installed a ls6 intake on my 2000 ls1 and the bottom is flat and it might have pinched the steam line.....which comes out the back...makes a lot of sense./... it happened exactly when they did the work..... new heads, new cam all new top end parts headers, oil pump fuel pump, injectors and a used ls6 intake manifold... the blower worked perfect before I dropped off the car... I checked.. I could see a rubber or plastic hose ... they all looked aluminum. there was a plastic hose that cracked that connected a plastic line to a metal port coming out of the valve cover..... I just put a hose clamp on it tonight for the time being....its only about 2" long ans slightly angled..i don't think that's what you are talking about though.......im calling the shop tomorrow and putting the ls6 intake scenario to him.......see if he made a conscious effort to avoid that pinch!

raggy 00

this is the article I am referring too: https://www.corvetteforum.com/forums...fications.html

Bill Curlee

ALL of the HVAC vents are vacuum controlled. When you loose vacuum, you get what you are experiencing. The vacuum source for ALL of the C5 vacuum controlled functions comes from the back of the intake manifold. There is a small port off of the MAP Sensor fitting. It connects to the nipple with a small rubber 90 deg boot attached to a very small NYLON Vacuum Line. Its VERY short and very difficult to get it to stay on when reinstalling the manifold. I lengthened mine for two reasons. One reason is,,, its way too short and difficult to keep it on, and the other is I have a FAST 90 and the vacuum port is on the side of the manifold now.

Vox Machina

H'okay. So the steam lines have nothing to do with vacuum or your hvac. Those are just for coolant.

Bill is 100% correct. I had a hell of a time keeping it attached when I did the motor in my Fbody. Get behind there with an inspection mirror and see if it's attached.