Howdy Kids Haven't been here in a while, been building my 73 VW beetle. I find with my 87 L98 the cooling fans don't don't come on until it hits (107C) 125F and cuts out at about 212 (100C). IMHO this is WAY too hot for aluminum heads.

S I want to change things so the fan comes on at about 200F and cuts out about 180. I've done quite a bit of searching but can't seem to find information on how to go about bringing around the changes I have to make. ANY help finding links or threads or info on this subject would be greatly appreciated. Thanks phatty.

 

A high flow water pump. Will knock temps down 10deg.
Typically the HV pump is so strong it collapses the bottom hose. Needing a copper wire coil to eliminate the hose collapse.
The best way to control the fan speeds and temp parameters. "Controlled on eprom". Is update the tables.

convert to a Eeprom. Or update factory UV. Both require sending your PROM out burning the new parameters/ tables.
Or purchasing Eproms. Pocket promgramer, CATS or tunerpro. Update burn.
Changing a sensor. Still controlled via PROM.
Some hack up the fan relays with a hotwire.

 

Thanks Admiral, didn't understand any of that.

 

How about selecting 4 options
All... samples only.

(1) high volume water pump.
Example> https://www.summitracing.com/parts/s...kaAn02EALw_wcB

(2) temp sensor kits. I believe with a resister to trick the computer

(4) bypasing the fan relay. A jumper is spliced in to force the fans on permanently.

(3) computer tune> https://www.ecklerscorvette.com/elec...wer-chips.html

 

Your fan temps are normal

 

Looks like you have C3 hub "spinners". I bought some years ago thinking they were the correct size for the centerbore. Apparently, you proved it! Good job.

As for the temp change, I would agree you're "normal". Moreover that it's not "bad"....meaning a change would be for your peace of mind more than the car's.

To change it, their are 2-3 ways. First you MUST change the thermostat because it will hold temps above your desired range. I'd suggest a 170...though they are hard to find. Not impossible. Or...settle on 185 for a turn-off temp.

The computer (ECM) controls the fan on most C4's. Not sure if early ones are controlled by fan switch near #1 cylinder? If the later, find a replacement switch in the range you want. You may need to change the connector as the range you seek often has a different connector. If computer controlled, you either need to get a new (reprogrammed) prom -- the chip inside) or bypass that circuit and buy a fan controller. Or...use that plug (switch) near #1 cylinder to control your fan. I said plug in case the hole is plugged and no switch is installed.

 

Thanks, I understand those. Much appreciated. Just to clarify the normal highway running temp is not a challenge it is the sitting in traffic spikes.

 

Over 40 mph in most cases fans are not necessary. Fans are controlled by programming in prom. There are aftermarket proms that lower cooling fan on and off temps. Some require 180 thermostats. Make sure condenser and space between condenser and radiator are clear of debris.