<U>Engine</U>
1998 B18B completely rebuilt, GE Sleeved, 83mm, going straight LS-Turbo

<U>Car</U>
1998 GSR Shell

I rebuilt the LS engine and put it in the GSR shell I had, the 2 heater hoses did not match exactly so I routed them as shown below.

<U>Problem</U>
OK, I start the car, let it idle and the block and upper radiator get very hot, almost too hot to hold your hand on. However, the lower radiator hose is ambient temp(actually feels cool). Now I know this will be the case until the thermostat opens, but I am nervous of letting the car run thinking there could be a problem. My temp gage reads about a 1/4 of the way, and no radiator fans come on.

<U>Questions</U>
How long is it safe to leave my car idling if I suspect a cooling issue?

What sould happen first, the thermostat opens, or the radiator fan comes on?

Am I just being paranoid and should let the car run longer then the 5-10 minutes I let it run?

Should the head and upper radiator hose be so hot that I cannot even touch them?

Where is a good place to put a thermocouple if i want to measure the temp with an independant device(not sure if I trust the cars temp gage)

Is there something burning me because the motor is a LS (and wire harness) and the car is a GSR?

I appreciate any advice you can offer, or how long it take for the thermostat to open or fan come on, etc(at idle condition). Im in NY and it was about 60 degrees outside when I did this.

Here is a pict of the heater hoses I routed to match the GSR:

 

Trust your coolant gauge! The temperature of the returning coolant circulates through the entire engine before it goes back through the top hose and back into the radiator, therefore, it's normal for your top hose to get hot. This is actually a sign of good coolant circulation!

As far as your bottom hose being cool, this is also a good thing because it means your radiator is doing its job by dissipating the heat. I'd say you're totally good to go. Go break that thing in!


*From my experience your hand can't really tolerate anything over about 120 degrees, and an engine usually gets a bit hotter than that for optimal running temperatures, so yes, I have found my upper hose/valve cover EXTREMELY hot to the touch as well.

 

Ok, is there circulation of coolant in the engine when the thermostat is closed? There can't be any flow through the radiator if the outlet of the lower hose is stopped by the closed thermostat right? It seems like when I let it run the upper radiator hose is being "packed" with hot coolant that has no where to go since the radiator is full and flow is stopped by the closed thermostat. Maybe I dont understand the fundementals of the system? It's hard to determine if I have flow through the system which is one of my fears

 

take it for a test drive to get some air flow over the radiator and see if that helps... your thermostat should take about 170-180 degrees for it to open...depends on which one you bought

 

I have the Autozone Duralast, I think it was?

 

I have the exact same problem in my 94 LS so i dont think it has anything to do with the fact its a GSR shell. But i bought a brand new thermostat the other day and it doesnt make a difference my fans won't turn on either and i can run it like all day, and the gauge will stay at a little less than half way. and i don't think no offense to anybody they know how hot our motors are gettin.

 

i've seen just about every car i ever had take a good half an hour for the fans to come on after a coolant flush. and thats with me revving it over and over and over to help it get hotter.

your cars normal running temperature is just below halfway. if your car is at idle for 30 minutes at normal temperature without the fans turning on DONT WORRY ITS 100% NORMAL. some motor just take a long *** time for the fan to turn on.

 

alright cool maybe we are just so used to crap goin wrong that when somethin goes right we get all miscombobulated thanks a bunch

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18CUL8R &raquo;</TD></TR><TR><TD CLASS="quote">i've seen just about every car i ever had take a good half an hour for the fans to come on after a coolant flush. and thats with me revving it over and over and over to help it get hotter.

your cars normal running temperature is just below halfway. if your car is at idle for 30 minutes at normal temperature without the fans turning on DONT WORRY ITS 100% NORMAL. some motor just take a long *** time for the fan to turn on.</TD></TR></TABLE>

Yes I agree. I let it run and actually had a hand held laser temp reader and watched the temp come up to about 199-201 and the lower hose started heating up (meaning the therm. opened) and then the fan kicked on about 5 min later.