Heat/Overheat Problem

[jasontiff]

Pointless update: I didn't have time to check the hose size last night (to bypass the heater core) or swap the cap, so I'll try to get to it tonight and report back in.

 

[dave6666]

Pointless reply: Thanks for the pointless update.

 

[cayman]

You know, I see a lot of postings comparing run temps between various cars and setups. I can only assume that most temps being compared are based on what the temp gauge shows. Two things:
1. Just how accurate are the Viper temp gauges and/or temp sensors from one viper to another?
2. How accurate can you interpolate temps when the needle on the gauge fall between tick marks, especially given the fact the scale is non-linear?

Don't take this as sarcasm. I truely would like to know.

 

[jdeft1]

Yea, I know about the differences between the early gen 1s and later....

Still, I'd say it's time to upgrade....

I have a bad feeling about your car. A blocked heater is unusual to say the least... and it says bad things about the rest of the cooling system.... ???

Yep, another pointless update....
- J

 

[jdeft1]

Solution found!:

Buy beer...

Bring car to Dave6666666666666666666666666666666666666666666.

Walk away. (Buy more beer)

Dave will have a beer....Think a while.... hummm.........

Paint it white (a very cool color)...!

Ummm, yeah!!!!





















Shame on me!... I don't know Dave but I know he has a good sense of humor and he's good with a wrench.... Two very good qualities in your situation!

- J

 

[dave6666]

I do work for beer and dead animal parts.

 

[jasontiff]

I put the stock radiator cap back on and bypassed the heater core. It's about 80˚ right now at 1am and I went for a drive. When I got on it it'd get up to 230˚ (right before the yellow on the early RTs) but as soon as I let off it'd settle back down to around 200˚ over the course of 2-3 minutes. At cruising speeds and low RPMs the car stayed at 200˚ consistently, which isn't what later cars do but is a huge improvement for mine. The heater core was definitely partially blocked, but to get down to 170˚-190˚ I'll probably have to swap the fan and radiator. I'll stick with this over the next few weeks and see how it does during the day and in traffic.

Thanks to everyone that has chimed in!

 

[dave6666]

That really does sound like an airflow or cooling capacity issue. When I get on it in my '01 the temp actually goes down, as I've increased air flow at that point.

 

[-FROG-]

Sweet! Now, since you changed 2 things at once, it may be a good idea to go back to the other radiator cap and see if it changes anything or if it remains in the same state it is in now. This way you will find out what helped out the most. So if it was just the cap, then you can go ahead and hook the heater back up, if that is the case.... If you ever sell the car, it would be good to have the heater working. Still though, I wonder if your car is cooling just fine, but just a gage difference and that yellow mark psychologically looks like it's running hotter.

 

[jdeft1]

I think the stock t-stat is 192? deg. A constant 200 on the gage sounds high but OK to me... in that case. Swap to a colder t-stat may help a bit but you should still look into updating the whole cooling setup...

 

[dave6666]

Another option: Move to Alaska where all the people that say their car runs 180 have to live. I would love to bring some of those cars to Texas for testing...

 

[dave6666]

OK Jason. Sunday was beautiful weather. At least in Fort Worth

So what did you accomplish?

 

[jasontiff]

OK Jason. Sunday was beautiful weather. At least in Fort Worth

So what did you accomplish?

I accomplished confirming that the car stays cool at highway speeds, but it got damn hot again when I had to sit in traffic for about 10 minutes. Fixed, but not really. I'll try it in a commute tomorrow and see if that's any better. Still need to do the IR thermometer and see if the gauge is accurate.

 

[luc]

The water temp gauge is far from being accurate
On my 00GTS, it's off by as much than 15* and as mentioned, it's not linear.
I thought that my car was running too hot until I connected a scanner to the OBD2 port and verified the temperature.
Luc.00GTS

I accomplished confirming that the car stays cool at highway speeds, but it got damn hot again when I had to sit in traffic for about 10 minutes. Fixed, but not really. I'll try it in a commute tomorrow and see if that's any better. Still need to do the IR thermometer and see if the gauge is accurate.

 

[GR8_ASP]

Just saw the post and have a few comments. First is that 92 and early 93 cars have a unique cooling system that is very difficult to fill. Having air in the system will cause all of the problems mentioned. Best way to fill the system is to park nose down on a hill and fill through the heater hose. Squeeze the large hoses to make sure you get all the air out.

Bypassing the heater core should not result in an improvement. The heater is on a circuit that is closed when the heater control setting is on cold. Therefore in warm weather there is never any heater circuit flow. What it can do though is allow air to move more readily, preventing an air lock on the engine side of the thermostat (note some thermostats come with a small bleed hole just to prevent that problem).

Again my guess is that it is an air issue. If it is good for a while and then gradually worsens then it may be that you have combustion leakage into the coolant system.

 

[Tom F&L GoR]

Again my guess is that it is an air issue. If it is good for a while and then gradually worsens then it may be that you have combustion leakage into the coolant system.

Based on the "feeler" post you have new head gaskets, so I hope that isn't it. Radiator cap details? The old one may have hardened gaskets.

 

[bluesrt]

bypassing the heatercore will help but will still run hotter that a good flow heatercore in place,just a keep in the back of your head thought to know..

 

[jasontiff]

Based on the "feeler" post you have new head gaskets, so I hope that isn't it. Radiator cap details? The old one may have hardened gaskets.

The old radiator cap was less than 2 years old and appeared to be fine. I essentially have brand new engine gaskets all the way around; anything that could be replaced was when we did the heads/cam was done. I didn't want to be back in the motor.

 

[Ricksnake1]

Could the new head gaskets have been installed upside down or backwards? Not sure if that is possible on a Viper motor. But if so, there could be cooling passages covered by the gasket.

 

[GR8_ASP]

bypassing the heatercore will help but will still run hotter that a good flow heatercore in place,just a keep in the back of your head thought to know..

Not true for Gen I/II Vipers. The heater core is not full flow. It only flows when the heat is turned on. But, as I indicated earlier, flow through the heater circuit can help keep the thermostat in the coolant flow allowing it to open when the coolant gets up to the tstat opening temp. The thermostat may be in an air pocket and not open as it does not sense the coolant temp.

 

[jdeft1]

Update the cooling system!!!

 

[dave6666]

Sell the car...

 

[-FROG-]

Could the new head gaskets have been installed upside down or backwards? Not sure if that is possible on a Viper motor. But if so, there could be cooling passages covered by the gasket.

He just did alot of head work and it was running hot before the head work. So I don't think this would be a cause, but good thinking though.

I still think the car just has a funky gauge or reads hotter than it is. If it's the heat in the cabin area bugging you, well my RT/10 used to light my show laces on fire at times during the summer, but I was used to it from other hot rods in past years so I didn't care. The car's interior does get really hot in the RT's here in Texas. If your interior is hot, but not causing any 1st degree burns on your legs, then it may just be the gauge misleading you. I think it's a REALLY good idea to do the laser test you mentioned. It would be cool to let 2 Vipers sit in the shade for an hour. Grab a pin and paper to write down temp values, shoot them with the temp laser on the intake manifold or some other identical location around the motor / radiator and then take both cars on a little cruise, trying to maintain the same basic driving patterns. Then shoot them both with the laser once more to compare. Then do the same on a highway and traffic test.

 

[00SVTdubs]

wish I would have done a bit more research before buying this car... Im having the same deal. It runs great until slow speeds/traffic/idle then gets into the yellow on the gauge. If I shut the car off, the fans then come on in a min or so and stay on for a while.

sweet... maybe its time I sell this one and get back into a GTS or SRT10 this time...

anyone want a sweet RT10 for $20k? -

 

[jasontiff]

I was told by the guys at ART that if you swap the cooling system for a later Gen. I or a Gen. II it'll be fine. That includes the radiator, fan(s) and fender-mounted coolant bottle. Weaver said that when he worked at Maxwell they had to buy back 2 different early RTs when they couldn't fix the cooling problem, but resolved later issues by updating the cooling system.

 

[Dan Cragin]

92-93 models are unique as far as the cooling system. The fan cannot be upgraded as the dual fan system on these cars is built into the radiator support. I prepared and delivered these cars when new, most ran into the yellow mark when pushed. Thats why they got rid of the yellow mark on the gauge in 1994. Many of these cars also had liner extrusion problems in the block, hydrocarbons in the coolant would be the result and they would overheat.

Our fix was to put pusher fans in front of the radiator. We did this when we added on AC and the cars would run 190-210 on the gauge.

Hope this helps,

 

[eucharistos]

for dan

http://forums.viperclub.org/new-products-supplier-specials/630458-gen-2-cooling-issues-resolved.html

from dan

 

[SnakeInTheGulf]

Hey Jason
Did you ever put the manual switch in for the fan? I run mine 100% of the time! My 93 has and will allways run hot when hotdoging. or racing over long distances, but after I put in my switch 80% of the problem just went away, (more airflow) now I just watch the gauge and back off when I must.

 

[Tom F&L GoR]

Agree with Dan. I have a Roe duct which helps when at speed, but at slower speeds the cooling difference I saw between my original '94 fan and a replacement '98 (?) and up fan indicates that a good fan is the way to go.

 

[Bolt]

92-93 models are unique as far as the cooling system. The fan cannot be upgraded as the dual fan system on these cars is built into the radiator support. I prepared and delivered these cars when new, most ran into the yellow mark when pushed. Thats why they got rid of the yellow mark on the gauge in 1994. Many of these cars also had liner extrusion problems in the block, hydrocarbons in the coolant would be the result and they would overheat.

Our fix was to put pusher fans in front of the radiator. We did this when we added on AC and the cars would run 190-210 on the gauge.

Hope this helps,

This man knows what he is talking about. I bought the pusher fans from Dan and what a difference. Notice the layers of stuff the air must flow thru for one stock sucker fan. What a task for one fan. Multibles are definatly needed.

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