I don't know...sounds like malarky to me. LTx's aren't long gone...I have one, and it happens to be as "early" as it can be; a '92. I run the wee out of it, and there are no issues with air bubbles anywhere. The article I posted says the opposite of what you're saying from an article you can't find, so long ago, you can't remember. Oh well. I'll go back to not worrying about air pockets in my early LT1.

 

Greg,
Even our vette's have reduced timing as the temperatures go up, (which means reduced power). I have attached the timing retard curve vs. temperature on a stock 1989 vette. As it shows the timing starts to get retarded after the water temperature exceeds 197 degrees. (The numbers from one cell to the other are linear interpolated so by 208 degrees you have 1.6 degrees of timing pulled at higher load values)

 

Well Tom I guess you Have a photo graphic memory and can sight every thing to perfection you ever read.AS to GM's Fixing the air pocket problem or just making it passable You or I don't know.I am glad you like your LTX many owners do. I have a friend who is building one right now.

 

Sayyyyyyy WHAT? Where did that come from? I never made any such claim...did I? If I did, please let me know where I said that so that I can correct it right away. My memory is at least a weak and fallible as yours. No one remembers every detail/context etc. That was my point.

 

Easiest way to get rid of bubbles if they are there is to make sure the pressure cap is good and will go to full rated pressure and have a quality water pump that will generate additional pressure in the engine block. That will move the bubbles along with the coolant and flush them out.

 

Point taken and acknowledged.And I will admit that I Really like the LT1-4 and Mini Ram intakes Because everything on them is accessible and easy to work on.i met a man who said he was never wrong.He thought he was once But he said he was wrong

 

Those are some wise words. If you ever find that article, please post it up.

 

Now that we've talked about a couple of specific ideals, let me propose an ideal for this thread.

I spent quite a bit of time trying to consolidate the things I've learned about cooling along with the hard-to-find considerations when looking into cooling issues. From what I know, they may be more prevalent in the L98 because air flow and the stock fan are "borderline".

In looking at fans, I found the topic very complicated. Aptly, some people would argue just throwing parts at a problem is a bad/costly approach. I agree because I don't like doing things over.

The issue of fans is challenging because it's not obvious "how much" fan might be needed for improvement. I've compared what my car does at intervals from stop to 40mph...and higher. I've read people using wind meters to see what fans put out. I "Googled" and found little about thickness of radiator versus static pressure. Documentation on fans can be sketchy, inadequate, or contradictory.

Then you have to look at the dimensions/compartment of what you are dealing with. Will dual fans work/fit? Is it better to stick with the stock configuration? Are there ANY fans that will provide enough bump to really meet your target/goal? What about wiring and amperage supply from the stock system? If you want better cooling at idle, is an electric water pump the better option? Are high-flow water pumps any better...especially at lower rpms? I also mentioned cleaning and provided a link to a few related threads with their own level of feedback/detail.

I was actually surprised how much looked, digging, and research I've had to put into this subject to figure out my options. After doing so, it just seemed obvious there needed to be a consolidation of this information. That's why I contributed this thread...and especially the OP.

As I more forward, I'm ruling out some of the options I originally hoped to be the best ones. People don't post important things like aftermarket power usage of fans (like Mark VIII) versus the "real thing"). Like any other "knock-off", copies might not perform the same. Chinese-made is...and Chinese-made does! [wink]

Yesterday, I was really hep on the idea of converting a late-model dual fan setup to my earlier car. Now I don't think it will work because later cars have a "slanted mounting" which allows for a taller setup. The late model fan shrouds are too tall in an L98. (And the fans "sit" all the way at the top/bottom -- eliminating the option for trim-to-fit)

I looked outside the box too....to brands less obvious....Flex-a-lite, Durale, and even the new brushless models.

I've compared their flow, amperage, static performance, and even tried to correlate CFM to MPH. That's because the real goal is to duplicate what your car does "at speed" so cooling continues just as successfully at a stop. And, it might be possible for the average person to drive (at lower speeds until they find the MPH/CFM necessary to meet a personal goal.

Again, mine was to stay below 200-deg. This thread contains a timing table AND a link that shows why that can be an advantage. Modified setups (like my higher compression stroker) raise the heat-load over stock.

When people think of modifying a motor, often they might not consider transmission/differential "impact". The more I looked at this issue, the more I think cooling should be as important a consideration as transmission, rear-end, and tuning. At the very least, there's a lot to think about which made me think this forum needed a place to consolidate it.

I think what's posted so far has good interest on the topic. I hope even more practical things you can check/do will be presented. I like that a late model radiator swap thread is being circulated. I was thinking of starting another (with pictures of mine) for how older radiators are removed. With all of the extra things I've already thrown into this thread, maybe the word "fan" should be removed from the title?

 

I wasn't going to say it but since you feel it should be a cooling thread there is a lot that hasn't been mentioned on radiators and what makes one cool better than another.Adding more rows and a thicker radiator is not necessarily the answer to running cooler.A thinner radiator with larger wider cross flow tubes has been shown to cool faster and better.

 

An examples (specific models) you'd like to share? I think people would really be interested in specific comparisons, specifications, etc....

For example, in my OP, I tried to compare fans by amperage/cfm. After my digging, it looks like dual 11" models outperform single 16" units. But, adapting the dual setup presents some challenges. The easiest one to adapt appears the less-likely to bump the best 16" model. (BTW...if you compare sq/in of the two options they are actually pretty close. I originally thought two 11" would be WAY better than 16's but I think anyone claiming 2700cfm per 11" fan is wrong.)

Something I read recently suggested 100CFM per amp was a good rule of thumb. To me, that fits. In looking at fans, a lot of people may notice FFDynamics advertises a 3600cfm unit. I've always doubted that claim because specs show it at 18 amps. IMO, that would put it below the SPAL options pulling 22, 24, or 26 amps. With that as a reasonable guideline, it's more likely to assume FFDs draw 1800cfm (or less) and are over-stated. If their ratings are that over-stated, I'd doubt their lifetime warranty claims too. Heck, I had trouble even contacting that company a couple years ago.

Apply that to radiators and you might suggest cooling ratings, longevity, price-per-whatever....or even a link to threads where people swapped from brand-x to brand-y and saw improvement.

 

Gregg As far as siting particular brands I can't really tell you which ones are built according to the article on what works and what doesn't.all I can tell you from memory is that a radiator with two rows of 1 inch wide cross flow cooling tubes will cool better and faster than one with 4 rows 0f smaller width.I went down to look at my radiator and sure enough it has very wide cross flow tubes.When my Vette gets up to temperature and the single fan comes on it bring the temps down fast.I think Chevys mistake is not having two rows of 1 inch cross flow tubes.At least not that I could see .I'm pretty sure it is the original radiator But I don't know its full history.

 

Before I have to take the primary fan motor out of the car for the second time this week I have a question I am hoping somebody can answer. Are there any different types of connector to plug into the fan motor? I ask this because I replaced the primary fan, after running a jumper between pins A - B on the OBDI connector and only the secondary fan turned on. After installing the motor I am unable to plug the connector into the fan. Any type of adapter? BTW, I have a 1990 Convertible, L98.
Thanks,

 

It seems obvious that you've likely/maybe purchased a wrong motor or it was misboxed. What brand and part # did you purchase?

This is the connector I would have expected on a cooling fan motor:

 

I purchased ta VDO Radiator Fan Motor, PM537, from Autozone. It's probably true that I ended up with the wrong part, had to ask before I have to take the fan shroud out again. At least the second time will be easier, there is a great thread on here with detailed instructions, including pictures.

Here is the link from Autozone that says it fits my car.

http://www.autozone.com/cooling-heat...tor/129804_0_0

 

Check your link and there's an image of what should be expected for the connection on that motor package. 3d image from left. If packaged correctly I'd think should fit. You should be able to check with a mirror I'd think. Compare to your old motor! See if AZ has an equivalent connector to a GM# 12101917 ACD PT189 and try that on new and old.

 

That's a good idea, thanks, will swing by AutoZone and compare the connector on both old and new. When comparing the connector shown on the AutoZone page versus the one on the old motor they look basically the same.

 

So I took the old fan motor by AutoZone and still had no luck finding one with the same connector. We compared the old one to a fan motor for an 89, 90 & 91 and they were all different than the old one. I'll go by another parts store tomorrow and see what they have, if that doesn't work I will look at replacing the connector.

 

I would think that AZ should be able to contact VDO and get a suggestion on a connector to resolve your issue. If you've got the motor/fan/shroud already assembled and in the car I believe I'd like AZ to supply the connector OR tell them to give you some consideration for the labor. IF YOU DON'T ASK THEY AIN'T GOING TO OFFER!

 

It looks like OReilly's sells the same motor. Once I went to a local location where they pulled out a large variety box of "weatherpack" connectors. It's possible OReilly's has a better selection on plugs?

It also looks like you might [just] be able to crimp on a couple of female spade connectors and push those into the motor. If you wanted to get creative, you would coat the inside of the plug with grease/oil, wrap tape about the outside of the receptacle (to extend it), and "pour" in epoxy or fiberglass to mold your own plug. Might not come out (or work), but it's a creative option if you run into a brick wall.

Conversely, if you can find the right type of plug -- as far as spades and spacing -- but the receptacle is wrong, maybe you could cut away some/all of the outer receptacle wall(s) with a dremel.

Finally, there IS a website for VDO where they might be able to point you to the right plug (part#), vendor, or both. The website is www.usa.vdo.com

 

I did some more research and the following fan motor, AC Delco fan motor #617305, fits 90-96 C4s and 97-2004 C5s according to the AC Delco website. I am going to take the old motor with me to Advance Auto and see if they have the fan motor, AC Delco or other similar fan motors for the same application, that I can compare plugs before I buy it.
Thanks for the suggestions. I will post my results when I am successful in case somebody runs into the same issue.

Here is the link to Mid America Motorworks listing the AC Delco:
http://www.mamotorworks.com/Corvette...motor-617305-1

Update:

I purchased a CARQUEST fan motor, part # 35379, and everything is working finally. I did end up replacing one of the fan relays as well, but both fans work. I believe I also found my next project, while listening to the car idle, waiting for the temp to get high enough to trigger the fans, I noticed a rattle noise, I believe it is coming from the water pump. If so that would explain the fluid that drips under the car, I bet it has the original water pump and it's dying of old age.