Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Hey guys, I have a turbo b16 with a AEM ecu, I recently installed a aftermarket water temp Guage but the Guage is showing a different reading from the temp the AEM shows, I installed the Guage sensor on the top radiator hose, the Guage is Reading 12 degrees cooler than what the AEM is showing, shudnt the 2 be showing the same reading?

Cooling system is a double core half size aluminum radiator with oem thermostat and spal fan

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

What guage?

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Well it's a electrical Guage, think the brand is hotsystem, didn't tink i needed anyting fancy jus to show the coolant temp

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Helps to know what peripherals like that play nice with your given EMS. It could be variations between that particular guage and your AEM. I'd inquire with an AEM tech advisor and see if there may be any concerns on that particular front. :cheers:

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

The Guage is independent of the AEM, I get the temp from the aem wen I connect my laptop and bring up the engine data, I ran this aftermarket Guage to the top radiator hose

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

I just want to know if the coolant in the top radiator hose and where the engine coolant temp sensor is should be reading the same temperatures

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Yeah, so basically you have the AEM giving a reading and then another guage (one that came with the sensor I presume) giving its own reading? That's what i mean by variations in each other.. The AEM and whatever guage you're comparing it to. ;)

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Your other gauge sensor is threaded into an aluminum oven, so I can see why there would be variance between the two.

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Isn't the head aluminum also, and the Guage on the top radiator hose it showing 12 degrees cooler than what the engine temp sensor is showing

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

I looked up the sensor kit itself and found it on Amazon. 67 reviews, 3 and a half stars. 25% of the reviews were 1 star and the majority of those complained of inaccuracy.

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

I have one of my gauges behind the block and one on the side and the temps are 10 degrees apart

re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Water temp Guage? Wat engine? Electrical Guage?

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

This is normal. My aftermarket water temp gauge is read from the top radiator hose and the factory sensor is in the thermostat housing IIRC, which is connected to lower coolant hose. So the temp at the top of the radiator is always going to be hotter. It is roughly 10 degrees like others have said (the aftermarket gauge always reading hotter as its right at the outlet of the head)

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

I thought the factory water temp sensor was connected to the head near the inlet for the upper radiator hose, the fan switch is wats in the thermostat housing

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Yeah you might be right. Either way, the differential readings you are getting is normal.

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

This is normal due to the different locations of the sensors.

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

So which one is showing the correct reading for the engine coolant then? Cause it's 10 to 12 degrees in difference which is alot, and most aftermarket temp Guages are installed on the top radiator hose

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Read it from AEM. :cheers:

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Yes but I can't drive around with my laptop Connected all the time which I why I got the aftermarket Guage

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Why's that? Po po that douchebaggish in your area?

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Technically they're both right, they differ because they're reading at 2 different spots. I'd go off the factory location (your AEM) because it was put there for a reason.

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Plus driving around with an open laptop and periodically looking at it sitting in your passenger seat is a PITA, safety hazard, and looks ratchet lol.

The gauge that's reading from the OEM location (directly in the head) is the "most important" one.

Kinda too late now, but why didn't you get a gauge that could have just displayed the result straight off the ECM?

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

Ok well you know its always 10-12 degrees hotter at the aftermarket gauge...Shouldnt be a problem.

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

I agree. it's actually good to see temps from two different sources. that means you really know coolant is flowing and working properly. Just know that it is 12 degrees higher than what the AEM sees. no need for laptop, now.

Re: Different coolant temperature readings between AEM & aftermarket gauge. why?
 

It's hard to believe that the coolant temp changes by all of 10 degrees by such a short distance as the factory temp sensor is very close to where i put the aftermarket sensor on the top radiator hose