: Typical warmup of a LT1?



N0DIH
02-25-05, 07:59 PM
I am suspecting I have a weak (lazy) thermostat, as my LT1 Cad seems to take around 10 min before I get any heat, blower comes up, but cold air. Despite having 3.42 gears, it is still slow to warm. But does have the mech fan trying to cool things off.

I picked up a stat today (Autozone :(, NAPA was out of stock), it seems to be a quality piece, but the autozone computer has a cheap one that is the wrong stat (buyer beware!!).

So before I change it, any advice? What is best to keep coolant off Optispark?

Any comments on if this is typical of these cars? My 91 Bonneville and 91 SDV 4.9 both warm up in minutes of driving, like 92C by 3.5 minutes of driving, no matter the temp.

Can I read the temp on the computer I/O on the Fleetwood like I can on the 91 SDV with the 4.9?

Thanks!
Tom

scurling
02-25-05, 09:46 PM
Tom:

I think my V4P is a little slower to warm up also. It could be due to the V08, heavy duty cooling system. My V03 Fltwd. with the two electric cooling fans heats up in about half the time. My wife noticed it immediately when she started driving that car this winter.

I almost purchased a thermostat from the local Advanced Auto. I was informed it was "OEM". I asked to look at it, and I almost laughed. It was so cheaply made, I couldn't believe they sold junk like that.

I really need to learn the diagnostic code center operation, so I don't have to read the manual every time I need something. It looks like the coolant temp. is pointer #24. Read in deg. celcius.

Others:
pointer -20 = current temp. valve position
pointer -22 = temp. valve position full cold (180 - 250) default is 180
pointer -23 = temp. valve position full hot (5 - 60) default 60.
pointer -25 = commanded temp. valve position (0 - 255) default 128

hope this helps.

N0DIH
02-26-05, 01:47 AM
Is there any posts that go over the diagnostics on these cars? I can't find i yet. I haven't got a FSM yet

I do have one for an 85, is it similar at all? I always felt the 85 was more like my 91. (HT4100 vs 4.9)

Thanks!
Tom

HotRodSaint
02-26-05, 01:38 PM
Have you flushed your cooling system?

From what I've read about the Impala SS, these cars are known for getting clogged heater cores.

There is even a service bulletin, that explains how to fush the heater core.

My first winter I flushed, but the second winter I replaced it. There are no heater issues this winter.

N0DIH
02-26-05, 02:25 PM
Being I just got the car a week ago I don't know the shape of it. I will replace the stat today and then look at flushing it, I would prefer to anyway, I don't have any idea when it was done last, I have the repair records, but I haven't seen that yet.

I fought with the heater core completely plugged on my 91 SDV, so unfortunately, I know it ALL to well, my feet FROZE for a couple weeks till I could get warm enough to flush it.

Thanks! I was hoping these cars were less of an issue for it, but it seems not. I have had several cars (76 Delta 88, 80 T/A, 91 Bonneville and a 91 SDV) and none have ever had to have the heater core itself flushed. But then again, I was religous to flush the system with that prestone kit yearly, so I guess that was enough to keep it clean.

Tom

scurling
02-27-05, 01:04 AM
I flush the cooling systems with my Fltwds. about every two years. I never use the factory recommended "tablets", and I've never had a problem with heat.

Evaluating the two different system (V08 and V03) and their hardware differences: The V4P is continuosly pulling air through the radiator. On a cold day, that will make a difference in the time needed to bring the cooling system, engine coolant and radiator coolant, to equilibrium.

Can anyone provide a copy of the service bulletin referencing the flushing of our colling systems? I would like to see how it differs from the service manual. I will almost bet it includes adding the tablets. The factory service manual clearly states to add two tablets when refilling the cooling system.

ShadowLvr400
02-27-05, 12:09 PM
Tom:

I think my V4P is a little slower to warm up also. It could be due to the V08, heavy duty cooling system. My V03 Fltwd. with the two electric cooling fans heats up in about half the time. My wife noticed it immediately when she started driving that car this winter.
hope this helps.


Heavy duty cooling system? The tow package comes with a bigger radiator or something? I'm figuring I'll need to upgrade my cooling system once I take the LT1 to a 383 LT1.

scurling
02-27-05, 04:05 PM
I don't think the radiators are different sizes, and both cars are currently not at home for me to measure. The V08 option uses a standard belt driven fan and shroud on the secondary side of the two fan setup. There is also an additional oil and trans fluid aux. coolers.

I'll look for radiator differences between the V03 and V08. Many heavy duty or extra capacity radiators will have an additional row of core tubes. I don't see anything stated in the service manual about radiator differences.

HotRodSaint
02-27-05, 10:36 PM
I will almost bet it includes adding the tablets. The factory service manual clearly states to add two tablets when refilling the cooling system.

I read about it in a post on the ImpalaSSforum.com.

I think the bulletin spoke of how to properly remove the brown gunk.

scurling
02-27-05, 11:42 PM
Thanks, I'll investigate. I don't think mine was too dirty this past fall. I used a heavy duty flush in one of my Fltwds. which I has not flushed for two or three years. It wasn't the typical 10 minute Prestone flush product. You installed it and ran it a few hours. It was dirty, but it didn't seem too bad.

N0DIH
03-12-05, 09:43 PM
Well I flushed the heater core last weekend.

Now I have it at 67-70 degrees and complain it is too warm!
It warms up much faster now, no issues with that. Still slower than the 91 SDV with a 4.9L, but I don't mind.

Tom