I'm scared

[visionary]

Hey, good luck tomorrow. All of us feel a little pride when another Z owner brings recognition to the ownership and heritage of the automobile.

I am glad the car has smoothed out for you. You might consider the option of a 3 core radiator. I waited a full year to replace mine (which had the original 2 core). During that time I had it flushed and reconditioned twice at a cost of about $50 US both times with no noticable results. On warm or just F---ing hot days the car always registered above the mid mark on the gauge and if I decided to push speed above 90 it was more to the 3/4 mark.

After replacing the radiator with a 3 core, I have run all day above the 90 mark with the needle barely touching the mid mark. This last trip was in daytime temps above 80 degrees at altitudes above 7500 ft. In fact, I hit Donner Summit (ask someone else where that is) at 95 with the mark at 1/3 and 1/3 left in the pedal two weeks ago....

The cost, after a little negotiation, was $212.00 delivered....

have fun

Keith

[BadDog]

That's not bad at all...

We had a total of 28 Z's there yesterday; they gave us 2 classes, but they didn't make any sense: they mixed ZX's with Z's It was a good show, there were a total of 986 cars, I think...

[billcapp]

All Baddog & all Z ers,

I've followed this thread and I don't see consistent results given.

Some points I'd like to make.

1. Has the temperature guage been checked for accuracy. I stuck a thermometer in my radiator to compare to the guage. I'm supposing that the middle mark is 160 Deg. If you use a 160 Deg. thermostat then it stands to reason that the operating temp is usually around 170-180 Deg. if everything else is normal ie. outside temp ~80 Deg. This means the guage should be reading just above the middle mark...am I wrong?

2. I do beleive that the AF mixture plays a role in cooling and release of heat. The recommended mix of 50/50 provides for the best protection of overheating (running too cool doesn't appear to ever be a problem) and too much AF will not provide enough heat transfer.

That given...how much coolant did you drain off and replace with water? Is your timing and idle now correct (7.5 Deg BTDC @ 750 - 800 RPM)? Did you also check your dwell...if so what is it?

Some other questions I still have.....

Just how much better will a fan shroud do ( in degrees of temp drop)?

Has any one looked into or experimented with oil viscosity differences as to oil pressure readings? Usually at 94,000 miles I would have an inclination to use straight 30 W, but with my Z having 180,000 miles on it ( still all original engine with not even a valve job yet) I use 40 W. My pressure always reads normal (almost to the bottom of the guage at idle (800RPM) and in the middle when cruising). I assume this is normal. Being in a hot climate 40 W should be used anyway.

How much better is a 4 vs. a 3 row radiator (in degrees of temp drop)?

Will a electric fan provide better cooling at idle than the stock (nylon with properly operating clutch) fan?

Will it make a difference with or without the shroud added? (On a '71 240Z)

Living in Florida, heat is always a big issue:( I used to have the dealer add-on AC (York compressor) and the engine always ran too hot. I had to turn off the AC every time I came to a red light; but this was before I replaced the radiator with a 3 core and replaced the stock metal fan with the later year nylon one.

I plan to solve this cooling problem so I can add a 280Z AC system. I'd like to still be able to drive during the summer months here (March to November) and you guys up north complain about driving in the winterLOL !

Well enough of this yak....if anyone has the answers to all the above, please be sure to address all issues raised into a complete package of the best solution for cooling.

I sure would like to know.

By the way, some other news to spread around. I used the newest coolant out - supposedly GM is now using a 5 year coolant (red in color - stupid idea) available from Prestone. My brother-in- law mechanic working at a GM shop said a bullitin came out discontinuing the use of this coolant because it causes premature wear of the seals (I never asked what seals).

The other news ( I posted this elsewhere) was I was told by a parts house that "water wetter" leave a buildup of residue in the radiator and shouldn't be used.. anyone hear anything about this?

Well I look forward to a lot of noise from you fellow Z ers.

[BadDog]

No, the temperature guage hasn't bee checked for accuracy.

My timing is hard to set accurately because (I believe) my cam timing is *way* off. With my distributor turned all the way clockwise, I get maybe 3 or 4 degrees BTD at 1,000 rpm

As for the rest, I'll only speak to what I know, or can hazard a guess on:

A fan shroud increases the efficiency of the fan in use. That's why they were added to later Z's (starting with the 260?)

I run 10W30 and my pressure is at around 80 when cruising, maybe 20 or so when idling. My old 280 was always at 80 or so, leading me to believe that maybe your oil is bit heavy for your oil pump (I could very well be wrong)

An electric fan probably would provide better cooling at idle; it would also give your water pump an easier life, and maybe gain you a HP or 2

[EScanlon]

The percentage of AF to H2O used, I referenced is right off the Prestone Bottle in my garage. At 50%/50% it gives one set of Upper and Lower temperatures, at 70%AF/30%H2O it gives a Higher Upper and a Lower Low temperature protection, the bottle does not address cooling efficiency.

I went to their website hoping to find some information and after a 10 minute search could not find anything that referenced the cooling difference between 50/50 and 70/30. Since I was looking for the sake of discussion and not for Doctorate Thesis; I let it go. I'm sure the answer is out there someplace, and if so, someone else is welcome to research it out.

Since the reply we have received after changing the mixture percentage does indicate a drop in the operating temperature, I feel we would be safe in saying that a 50/50 mix is more efficient than a 70/30. But not having had direct experience myself, I posted what I had learned from the bottle.

Personally, I ALWAYS mix 50/50, since a mechanic YEARS ago put it this way: "Rick, if the temperature drops to -35F or above 260F in the engine, you got a sh!tload of OTHER problems to worry about. Now if you lived in Alaska, then ...."

[BadDog]

I used Prestone, and before I did all this I took a quick look at the back of the bottle. 70/30 seemed to be better due to wider temperature range, so that's what I used. "Wider is beter", right? Wrong in this case Darned Pontiac commercials....

[guy_geo]

WELL WEL WELL,, It's really hot in Montreal thes last days, and today, it was 40C (around 105) with the Humidex factor close to 120F... Ouf.

Tonight, I went for a ride in the ZED and notice that the temp needle was falling in love with the other side of the temp gauge...close to the 250, maybe 210..

Put the heater on, no, it would'nt drop...

My ZED is running on a high timing ( I mean more advanced and rich carb also). I have a 2 core rad, thermostat was checked and now, tomorrow, I'm going for a 3 core radiator since I'll be using the car to go on holiday far from Montreal..

Any other advice regarless of all the posts here?

Thanks guys! :dead:

[2ManyZs]

Well, this is only my opinion, but if a three row is better than a two row, then a four row is the best of all of them. Since you can get a four row, I'd shell out the extra 50 bucks over the price of the three row and have a little more safety margin. All it takes is one time overheating and it's time for head work. The aluminum heads have little tolerance for too much heat. I have always run the four row radiators just for the extra piece of mind. Besides, if it is overheating with the four row, you know it's time to find out why.

[guy_geo]

OK, went to the rad shop this morning, the guy told me, nope, your rad is in pretty good decent shape for an old car.

I think I'll go with the bigger thermostat since I do not need to change the rad. I'll see what it does.

[Zedyone_kenobi]

Actaully, I have always heard that straight water gives the best cooling, the only drawback is the 212°F limit before it boils. If your car does not get that hot straight water works very well, however, it provides no corrosion protection nor any lubrication. If your cars cooling is in good shape, you can run water with a 'water wetter' type of product as they add lubrication as well as anti-corrosive additives.

Just a thought. I am going to dump some water wetter in my Z. I never really get above the middle line (3 core) ever, but I will let everybody know how or if it works.

[MikeW]

Possible new record - almost seven years since previous post.

[sblake01]

A couple of things. First of all, since the thread is nearly 7 years old so I truly hope any problems that were presented in it have been solved. Second of all 50/50 antifreeze-water mix gives the best cooling in my experience. Having tried most all of the other additives available over the years, it always comes back to water and antifreeze doing the best job under normal conditions. The key being what you said. ("If your cars cooling is in good shape"). I've run extensive tests with straight water also and you'd be surprised how quickly rust begins to form in an engine. So, straight water is something not even worth considering. Who did you 'hear' this from?

Edited June 8, 2009 by sblake01