First drive on the highway...some questions???

[USAFPILOT]

2nd will take you to 80MPH, passing is done is 2nd or 3rd.

[Roadster]

Originally Posted by efnfast

Tom, AC forces both fans on. Probably why you see lower temps with the AC on.

Yes, there is a difference, even though it is minimal with Marc's chip.

Originally Posted by XfireZ51

May want to consider pulling radiator and cleaning out the cooling fins. Over the years, fine dust gets in there hindering air flow.

Originally Posted by Racinfan83

That's the way mine was until I took it to Marc. I had him pull radiator and clean it, replace thermostat, and chip it among other things. I don't remember what temp thermostat he put in it - but mine hardly ever goes over 200 now no matter what... So maybe the radiator clean made a huge difference. That sucker was NASTY for having only 18k miles. The lower right third was caked with grease and dirt - Marc said the oil cooler lines has leaked and been replaced - but the oil got all on the radiator and they didn't clean that when they changed the lines. I made a debris screen to keep the bigger stuff out right after I got the car - but the rad was full of dirt and greasy junk...

Originally Posted by Paul Workman

Yes! x2 on that. The amount of sand and plant fiber that flushed out of mine was astounding. And, when driving, it is a good thing to avoid driving over the grass clippings resulting from people mowing along the edge of the road. (I found a thick mat of grass clippings pressed like cardboard against the top 1/3 of my radiator.)

Originally Posted by mike100

I found that residual mist and wet frame sections from the all too common oil cooler line leak will still allow dirt to build up even many months after the repair. As a general trend, i would say to clean the radiator every two years (from both sides). I clipped the pass. side shroud tab to make it easier to remove from the cluster of a/c lines and bracketry.

Besides the large debris, you still need to spray it through with water before each summer.

Thanks for the suggestions and the pic of the radiator, did that ever need cleaning!!!
I looked between my radiator and the condensor, and found one leaf. And it probably needs a good cleaning as everyone is suggesting. So I may do the hose cleaning front & rear first to see how much dirt I can loosen up. No time to pull the radiator, as the 74 is keeping me busy everyday for the next 2 weeks.

[Roadster]

Originally Posted by USAFPILOT

2nd will take you to 80MPH, passing is done is 2nd or 3rd.

I will keep that in mind, and try it out next time on the highway....thx....

[Roadster]

ok....some more questions....may be general C4 items and not just related to the ZR-1.

On the highway again today, and I've noticed that when moving at speed in 5th or 6th gear taching around 2k or less, that when driving over a bump or slight dip in the road, that the tach neddle will drop a few hundred rpm's and rebound over said imperfection. So is this a common problem with C4's? and what is the fix?

Also noticed that sometimes my volt gauge is all over the place, the needle seems to blink right along with the turn signals, no turn signal, no movement of the volt gauge needle. Also with dash lights lit, the lights in the dash will also flicker with turn signal usage. Common problem, or something I need to check further? I will have to check the digital readout when this happens, but haven't done so yet.

thanks for any info...................Tom

[edram454]

I have a manual fan switch. I can turn on one or both of the fans at any time. In Florida I always have both fans running and it prevents overheating. I should probably take and clean the radiator and get a new thermostat just in case but the manual fan switches are the best. Previous owner did a bunch of things like this on my car. I think he covered all the bases.

ed ramos #3028