i have a 02 blazer 4x4 4.3 vortec, the recently developed a overheating problem, i replaced radiator, water pump, and thermostat,, i am losing coolant, but it not on ground nor in the oil, nor is my exhaust smokey, also it when its floored it wont get over 25 or 30 mph,, i've been told it the intake gaskets, and i was also told it was the cat, i already cut cat off and straight piped it but no difference. What could my problem be?

 

That sounds a lot more major than this but the coolant might be because the system was not cleared of air properly and the cap is bad. The system is pressurized and if the cap is venting then it will loose coolant. The speed thing is way over my heard on the forum.

Good luck,
Nathan

 

How much coolant are you loosing each day? A blown head gasket could result in both symptoms but I would think that if it's bad enough to only allow 25mph you would have coolant blowing out of the exhaust. Did you do a compression test? It's also possible that the intake manifold is leaking and something else totally unrelated is causing the power loss. There are people here that know everything there is to know about the 4.3's but you'll have to do some basic trouble shooting. If your compression test is good then I'd start looking for other causes.

 

i have to put a 1/4 gallon in every time i drive the truck,,,, i've been talking to some friends and they said it sound like someone put sugar in my gas tank,,, no i have done a compression test yet due to not having the equiptment

 

if you have an autozone around you a compression test kit will cost you 40.00 to borrow for the day...i like the loan a tool system..saves me some good cash.

have you pulled the plugs and looked for signs of coolant in cylinder...worth the time.

just out of curiosity what are the standards for a "good" compression check?
i have seen/heard you need above at least 100 and less then 10% diff between cylinders.
anyone??

 

You must has pissed off someone pretty good....but I doubt sugar is the cause. Maybe it's time to stop listening to your friends and either bring it to a garage or do some testing. I was plagued by a small loss of coolant for a year that showed no outward signs of a leak either externally or internally. Turns out that a small drip from the intake manifold can burn off inside the block without ever going into the oil. Since water doesn't flow though the block until the thermostat opens it didn't drip until the block was hot and would vaporize inside the engine. One day it blew completely and 2 gallons of water found it's way into the oil which solved the mystery of where the coolant was going. Until that happened the engine ran like a top.

It's most likely that unless you seriously overheated the engine your leak is from the intake manifold but I think you need to find the cause of the power loss before you replace the gasket. It would be hell trying to troubleshoot a problem after replacing the manifold gasket if the car wasn't running right before you did it. Not being mechanics people like us get really confused if more than one thing at a time is wrong.

 

One test for head gasket leak would be to take rad cap off and start it up cold.If water blows out of the rad, well that would be a problem.

 

Coolant not moving in radiator

 

1/4 gallon is alot to loose. You would have to smell the antifreeze burning/leaking somewhere.I would guess your burning it up in your cylinders.it will run like crap with moisture in the compression. Put a compression tester on the rad if you dont see a drop right away just let it hold a while, take it off and then start it cold while someone watches the exhaust.

 

ok everyone thank you for your input, i have tried everything even the pressure test, the cooling system did not lose pressure when i pumped it up to 10psi, although the radiator cap was bad cause it lost pressure,, i changed the cap and rotor with one from the junk yard and it stayed the same. water not in the exhaust, water not in the oil, not losing water, found out the fan clutch is faulty, and i still need to replace it. my problem now is that the truck will not go over 20mph, or over 2000rpms,, will a distributor cause that problem or is it something else