Same old C4 problems

[corvette66]

Well I'm new to this forum. I have an 86' with a 4+3 trani. I've read and seen a lot of doug nash bashing on here. I have had no problem with mine. But.... the overdrive unit is junk!!!! otherwise the trani performs decently well.

But my problem, a typical c4 thing. My car is over heating. I'm sure there is a lot of posts for that. but in my case it's a little different from most peoples. I just replaced the head gaskets, water pump, thermostat, radiator, and all hoses.
doesn't always over heat, but it hits about 211 during slow traffic. 0nce in a while it hits 220, and boils over on me. Just wanted to have some people tell me their running temps. and see if they compare. wondering if my car is running at normal temps, or if it is time check all my electrical components.

by the way, does anyone off hand know the fluid capacity of the 4+3 trani. (not overdrive unit)

thanx for reading, dan

 

[Ken]

Thanks for not bashing the DN 4+3, it wasn't all that bad of a tranny.

Regarding the temperatures you say you see in traffic: it is nothing to be concerned about when you hit 220° F when sitting in traffic. It's a bit high as most will agree, but the engine was designed that way due to emissions concerns. The emergency fan won't even kick on until 232° F or so, which brings me to your statement about the cooling system boiling over when you see 220°. If that's the case, there is definitely a more serious problem you've got on your hands. I'd begin with a complete cleaning and flushing of the cooling system.

From there my guess is that the area between the radiator and the air conditioning condenser is clogged with debris. You won't believe how much debris such as leaves, pieces of paper, twigs, etc. gets caught up in there! It's a good idea just to remove the radiator every few years, depending upon where you live and drive, to inspect and clean that area.

The transmission lubricant capacity for the four-speed is 2.1 pints, with 3.45 pints for the overdrive unit. Recommended lubricant: GL-5 (Dexron II for the overdrive unit). Lubricant SAE viscosity: 80W or 80W-90(summer/winter), 80W (extreme cold).

 

[corvette66]

great

hey thanx alot. that was quick i just posted that. but yeah it overheated at 215 one time. that was before i replaced the head gaskets. but i'm glad to hear that it's normal. thanx a great bunch!!!
dan

 

[Mart]

I have an 86 and I get the same temps, slow traffic brings it right up there.

I used to be concerned about a problem but realized everyone else has the same issue.

BTW is your 86 early or late production.

Mart

 

[87NassauBlue]

Yes, those temps sound in the vette reasonable range. You are right about the debri getting caught between the radiator and condensor. These vettes are bottom suckers. By the way, your radiator might need a good cleaning. I saved my 86 cooling system with a procuct called "core restore". There is a guy with a company called "plating technologies inc." that makes this stuff. I think His website is platingtechnologies.com. Anyway, this is the only stuff that I have found that really works since the epa outlawed the old dupont number 7 cleaner. You would be really surprised what will come out of your system when you use this stuff.

Thanks for not bashing the DN 4+3, it wasn't all that bad of a tranny.

Regarding the temperatures you say you see in traffic: it is nothing to be concerned about when you hit 220° F when sitting in traffic. It's a bit high as most will agree, but the engine was designed that way due to emissions concerns. The emergency fan won't even kick on until 232° F or so, which brings me to your statement about the cooling system boiling over when you see 220°. If that's the case, there is definitely a more serious problem you've got on your hands. I'd begin with a complete cleaning and flushing of the cooling system.

From there my guess is that the area between the radiator and the air conditioning condenser is clogged with debris. You won't believe how much debris such as leaves, pieces of paper, twigs, etc. gets caught up in there! It's a good idea just to remove the radiator every few years, depending upon where you live and drive, to inspect and clean that area.

The transmission lubricant capacity for the four-speed is 2.1 pints, with 3.45 pints for the overdrive unit. Recommended lubricant: GL-5 (Dexron II for the overdrive unit). Lubricant SAE viscosity: 80W or 80W-90(summer/winter), 80W (extreme cold).

 

[corvette66]

thanx for your reply, mine is a late model. (i'm pretty sure) any reason in particular?

 

[tyrel]

I agree with everyone else. 220 is not an inordinately high coolant temp, especially if you're sitting in stop-and-go traffic with the a/c on. If you're moving along a highway or boulevard, then it shouldn't go that high.

The advice about cleaning the radiator is right on. I did it three years ago and my coolant temps dropped dramatically. Here's an excellent article:

http://www.batee.com/corvette/dcrg/readerstips/larsstuff/this_tech_paper_will_discuss_sim3.htm

It doesn't take that long, and even with simple hand tools anyone can do it in a couple of hours. If you have a lot of miles on your car or you live in the country, prepare to find lots and lots of dirt and leaves clogging the cooling fins.

 

[corvette66]

thanx for your reply, mine is a late model. (i'm pretty sure) any reason in particular? sounds like good stuff. i'll have to try it in my other vehicle. i replaced the radiator, so i know it's good, but yeah i should just flush out the whole system. thanx

 

[Ken]

All convertibles and late MY coupes had aluminum heads, that's why the question was asked I'm sure.

_ken

 

[Mart]

I'm just curious more than anything as to where the cut off point for early and late models is.

Mine is an early #09846 lookin for its brother on the line.

Mart

 

[corvette66]

hmmm

Well i thought mine was a late model. but i know for sure that i have iron heads. i'll have to check on my manu. date

 

[Mart]

Iron heads, early model. Very strong though.

Those numbers are the last 5#'s from the VIN, is yours close to mine.

Mart

 

[corvette66]

no not it's brother

i got 15762

 

[Mart]

oh well,

Black and silver sounds nice, never seen that combo.

 

[corvette66]

yeah

actually yeah, the black and silver is a really nice combo. i really like it. black on bottom half and silver on top. mine has been sitting in the arizona sun for all it's life. so she's all rough and snake skin like looking. but i'll get it re painted, prolly the same color. Hope to get a pic of it on here soon. enter it in the beauty contest. haha

 

[Ken]

I'm just curious more than anything as to where the cut off point for early and late models is.

Mine is an early #09846 lookin for its brother on the line.

Mart

From Mike Antonick's book Cor-Vette Specs C4 1994 - 1996 Models:

... The heads were redesigned and did make it in time for installation on all 1986 convertibles. Of 27,794 1986 coupes built, the last 8,549 had aluminum heads. For the record, here is the exact wording of the aluminum head delay letter from Chevrolet Public Relations.

• Introduction of aluminum heads #9428 sent 8/1/85:
  WARREN, MI--Introduction of aluminum cylinder heads on Chevrolet's 1986 Corvette will be delayed while the heads are redesigned to eliminate a cracking condition around the head attachment bosses.
  
  As a result, early-production '86 Corvettes will be equipped with cast iron heads.
  
  Castings in the water jackets area of the aluminum heads had beed thinned intentionally to reduce mass and improve coooling. Durability tests revealed the thinning weakened the structure enough to allow the bosses to crack under high stress.
  
  Design of the heads has been revised to alleviate the problem, and they will be placed into production as soon as testing confirms their integrity.

_ken

[size=-3]Silver/Black eh? My favorite color combination.[/size] :cool

 

[terrykrueger]

I think (just an assumption) that part of our problem lies with digital gauges. We have an actual read out of the temperature - unlike the family minivan which just has a meaningless red blurb on the right. I bet the minivan is operating in the same range.

 

[RoadReady]

Don't forget possibly the cheapest fix on the cooling system: a $6 radiator cap. Old caps loose spring tensions and the pressurized system (16 lbs. I believe) raises the boiling point of the water in the system.

 

[corvette66]

good deal

well from what everyone has said here, i guess i don't have much to worry about.

 

[Jeff Henning]

I just bought an 89 and it gets hot while going slow.
The first time it went over 220 I thought I had an emergency on my hands but when I checked with the neighbor I bought it from he said it will do that and the second fan comes on at 229.
He was right it came on at 229 and cooled right down, however it never boiled. Maybe your mix isn't 50-50.