I want a real water temp gauge (as opposed to the dumbed down factory one) and have seen where some are splicing in an adapter for the sending unit into the radiator hose. The upper hose looks to be the easiest but does it give the most accurate readings? Is the lower hose better or is there some other place better suited?

 

The top hose should be the exit for water from the engine. That's where it's usually measured.

 

Thanks chuckt

Anyone know the inside diameter of the upper radiator hose?

 

I hope I'm right that it's 1 1/2 inches since I've just ordered a 1 1/2-inch Auto Meter adaptor to be installed in the upper radiator hose - the one that's right up front between the MFE and the intercooler. Here's a link to the Auto Meter web site where they list two sizes of radiator hose adaptors and two sizes of heater hose adaptors.

http://www.autometer.com/cat_accesso...st.aspx?pid=15

I should have the adaptor in the next couple of days, then it's just a question of having the time to put it in. Instead of cutting out a section of hose I thought I'd just replace the bleed valve (on the rare occasion when the bleed valve is needed, simply loosening the sender or pulling it entirely will allow me to bleed the system).

 

The OD of the upper hose is a hair over 1.4" near the radiator. I'd call AM and change my order if it's not to late. With a 3/32 wall that would be right at 1.25" ID.

 

Great idea EddyM with the adapter taking the place of the bleeder valve. I hadn't thought of that. Let me know how it works as I'm still a few weeks (paydays) away from doing this.

 

As my grandmother was fond of saying "too soon old, too late smart" - they'd already shipped it when I called back - it was on my back porch when I got home from work yesterday. Sigh! I'll return it and get the smaller diameter one. Dummy that I am, I thought the darned things were based on OD of the hose, not ID, and it never occurred to me to ask when I placed the order.

Earl - I'll let you know how this works. I'm hopeful it will be pretty slick, but I reserve judgment until it's in and I know I'm getting a valid temp reading.

 

Hope this isn't too late - I got bogged down at work and have only now gotten the adaptor installed. Unfortunately, I don't have any digital photos to show it in place. However, I think it's going to work out just perfectly.

Once I got the right size from Autometer (1 1/4 inches, not 1 1/2), installation was easy. I had to run two wires - one from the adaptor to ground, and one from the gauge inside the car to the sender. Of course, you also have to wire the rest of the gauge - a power source switched via the ignition key, a ground for the gauge, and power/ground for the light bulb in the gauge.

Replacing the bleed valve means you need to loosen the sender itself to bleed the system, and then tighten it back up afterward, but that was no big deal because it's all right there in front of you - no awkward angles to work at. I'm seeing readings of around 180 degrees under normal load conditions (50 mph, a/c running, ambient temp of 85 or so) and up around 195 or so in stop-and-go traffic with a/c and ambient temp of 85 - 88.

One note about my readings - the gauge doesn't show any temp in the system until after the thermostat opens because it's downstream of the thermostat. Therefore, the idiot-light stock gauge shows completely warmed up before the aux gauge begins to register at all. Some other folks have plumbed the sender elsewhere so that it reads coolant temp from a location on the block, and they'll probably see their aux gauge start to move about the same time the stock "gauge" does. For me, that's not a major issue, and I appreciated the convenience of being able to work on the car without needing to put the car in the air or become something of a contortionist.

 

Thanks for the update. My gauge is still in the box waiting for me to do something with it. I like the convience of mounting it front and center but I'm torn with wanting to be accurate all the time, not just when the thermostat opens. More proscrastinating required.

 

You might look at the AutoMeter web site (link in my post above) - they also have adaptors for heater hoses, and I think I saw where someone else had done that instead of using the upper radiator hose. I don't have a diagram for coolant flow through the engine, but since my heater puts out warm air almost as soon as the OEM gauge indicates heat in the block, I'm guessing it's upstream of the thermostat. Splicing an adaptor into the heater hose upstream of the heater might solve your desire to be accurate all the time, not just after the thermostat opens, though you might need to do a bit of parts excavation to gain access.