Gain extra benefits by becoming a Supporting Member Click here find out how!
Classic Performance Products Classic Parts
Ciadella InteriorsAmerican Auto Wire Classic Industries
Chevs of the 40sDanchuk Catalog
Hellwig Products IncPerformance Rod & CustomEcklers AutoMotive
Nu-Relics Power Windows
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy



Username Post: Heater Hose Routing 88 350.        (Topic#350581)
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-11-18 10:53 AM - Post#2730687    

2 years ago, I replaced that "quick connector" in my manifold with a regular nipple and replaced the defective radiator. Since then, my engine has been running hotter, than with the old radiator. And I get this rush of water in the heater core upon startup. I have plenty of heat. I am not losing coolant. I have done a pressure test and the test for exhaust with the chemical on the radiator. It is possible that I have air in the system 2 years later, but. I am also wondering if I hooked the radiator hoses up incorrectly. I have the hose from the manifold going to the heater core connection closest to the driver side. The core connection closest to the passenger's side goes to the radiator. The manifold hose is larger than the one that goes to the radiator, so I don't think I swapped them. I am about to change my coolant. I'd like to solve these issues at this time. Is it possible I do not have the heater hoses installed correctly?



 
someotherguy 
Moderator
Posts: 28614
someotherguy
Age: 47
Loc: Texas
Reg: 08-01-03
04-11-18 12:12 PM - Post#2730690    
    In response to Blueseasons

The hose size differences do pretty much keep you from mixing the routing up unless you really try hard to get it wrong.

If you're hearing a rush of water in the core, you have air in the system. You shouldn't have air in there after all this time unless you have a leak somewhere. It may not be one large enough for you to notice, but there's a leak. Even if you do a crummy job of purging the air, after all these drive cycles, it would have purged itself by now - providing the system is full and there are no leaks, at all.

I chased a gurgle in my heater core forever. At one point I thought I had it solved when I discovered the upper radiator hose was leaking due to some corrosion on the water neck causing a poor seal of the hose. Replaced the water neck, no more leak there, but still a gurgle. Many months later I finally got the tell-tale small drip of coolant down the front of the driver's side head because my intake gaskets had finally let go. This was on my '94 5.7 with around 158K on it at the time. Had seen no visible indications of the gasket leaking prior to this. No drips anywhere, no coolant in the oil, etc.

Running hotter is an indicator too; if the system can't pressurize properly due to a leak anywhere, it will run hotter. That leak could be head gasket, cracked head, etc. or intake gasket, cracked intake, radiator or hose leak, etc.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-11-18 02:11 PM - Post#2730707    
    In response to someotherguy

Thanks for your time. I will agree it has all the symptoms of air in the system. I would think that if I had a cracked head or gasket, I'd lose coolant. And I don't. My rational mind says these symptoms arose only after I changed out that radiator, 2 new heater hoses and that nipple.The radiator I swapped out was not leaking for much for very long. I noticed the coolant on my driveway very soon and then changed it out. It was still running very cool. That air bleed screw is rusted shut, But I would think that after 2 years and many start cycles, the air would have purged. Since the heater hoses are correct, i'am just going to change the coolant and see what happens.



 
454cid 
Valued Contributor
Posts: 2666
454cid
Age: 45
Loc: West Michigan
Reg: 02-18-12
04-11-18 03:40 PM - Post#2730730    
    In response to Blueseasons

  • Blueseasons Said:
I would think that if I had a cracked head or gasket, I'd lose coolant. And I don't.



You don't lose coolant because:

You don't see any on the ground?

or

You don't notice the level getting lower?

I would say that both can be deceiving. If you're losing small amounts of coolant, either into the oil (intake gasket), or to the outside of the engine, it's going to burn off before you see it. If the level is disappearing in the overflow, you've got to be careful how you're keeping track of where the level is, and when are you checking it, Hot/stone-cold?


99 K3500 RCLB


 
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-11-18 07:10 PM - Post#2730756    
    In response to 454cid

Thanks! Good point of clarification. There is a "hot full" line embossed on my overflow. I have marked that with a marker so I can see it from the side. I have coolant filled to that mark when the engine is at temp, and it never moves, until the engine cools, then it goes down. I am careful to check it on a level part of my driveway. I am really not ruling out totally some kind of head crack or gasket, but I thought a pressure test and that emissions chemical test would rule that out. I paid $2300 for this truck 7 years ago. Then it had 76K on it. Now it has 120k. Of course, I have put money into it (new front end, pull engine to replace freeze plugs and some minor stuff). I am really hoping it's not something expensive because I don't think I'd invest the money to repair it. How long could a truck with either of these 2 conditions run without progressing to undrivable? It was like one day all good. Then after the radiator and that nipple, not good. I can't explain how those 2 things would change anything though as I have changed more radiators over the years than I care to remember without issue.



 
454cid 
Valued Contributor
Posts: 2666
454cid
Age: 45
Loc: West Michigan
Reg: 02-18-12
04-11-18 09:15 PM - Post#2730764    
    In response to Blueseasons

I would suspect the intake gasket or water pump before the heads or block.

The 350s are notorious for the intake gasket leaking to the crankcase...cooling system to oil, so I don't think you'll find combustion gases in the coolant. The typical symptom is oil that looks like a milkshake, but that's not always the case. If the engine is run a lot, the water will burn off. Eventually, if it's really bad, the oil will turn reddish (Dexcool) and sludgy.

Waterpumps will eventually leak at the weep hole... I've had that happen twice on my 454 (280K miles). It can go quite some time before you notice it, because the heat dries it up.

If you aren't noticing a drop in coolant in the bottle, start checking the level in the radiator when it's cold. Make sure something weird isn't going on, where it's not dropping in the bottle, but is in the radiator. If you've got air in the system it's got to be coming from someplace. I lose coolant from my intake manifold gasket, but big blocks leak to the outside, so it's not as big of a deal from an oil contamination standpoint. I plan to take care of it this summer, along with several other things I've been putting off.

99 K3500 RCLB


 
someotherguy 
Moderator
Posts: 28614
someotherguy
Age: 47
Loc: Texas
Reg: 08-01-03
04-11-18 09:50 PM - Post#2730768    
    In response to 454cid

From my experience plus everything I've read on others dealing with intake gaskets, the small block TBI is not known for leaking internally, only externally. The small block Vortec, with its plastic intake gaskets (factory) was the one notorious for filling the crankcase up with coolant.

If there's absolutely, beyond any shadow of a doubt, there is ZERO coolant loss over the long term...I might actually start to give some weight to the idea some have mentioned that using a regular hose nipple on the intake could contribute to some of the noise you hear in the heater core, as the factory quick-connect has a fairly small passage and can act as a restrictor. Can't say I have experienced that myself, though.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
454cid 
Valued Contributor
Posts: 2666
454cid
Age: 45
Loc: West Michigan
Reg: 02-18-12
04-12-18 12:18 AM - Post#2730769    
    In response to someotherguy

  • someotherguy Said:
From my experience plus everything I've read on others dealing with intake gaskets, the small block TBI is not known for leaking internally, only externally. The small block Vortec, with its plastic intake gaskets (factory) was the one notorious for filling the crankcase up with coolant.



Oh, I should have paid more attention to the year of the OP's engine. I was thinking 96 and up Vortec.

  • Quote:
If there's absolutely, beyond any shadow of a doubt, there is ZERO coolant loss over the long term...I might actually start to give some weight to the idea some have mentioned that using a regular hose nipple on the intake could contribute to some of the noise you hear in the heater core, as the factory quick-connect has a fairly small passage and can act as a restrictor. Can't say I have experienced that myself, though.



Interesting idea. Seems plausible. I've read about restrictors but it was Gen3 Corvette guys worried about too much pressure at high RPM going to the heater core.


99 K3500 RCLB


 
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-12-18 12:54 PM - Post#2730800    
    In response to 454cid

I hear the water usually at start-up in the morning. Would that less restricted nipple translate to higher operating temp? I don't drive this truck hard or hot. I'm retired and generally, take it to the gym several times a week and just cruising around town. Rarely on the highway. It does not haul and it's not a work truck.I would say it's driven less than 3k a year. I change oil every 3k and I don't do an oil change on it once a year.



 
someotherguy 
Moderator
Posts: 28614
someotherguy
Age: 47
Loc: Texas
Reg: 08-01-03
04-12-18 01:38 PM - Post#2730802    
    In response to Blueseasons

Nope. How hot is it running, and have you confirmed it with an IR temp gun? The gauge is not even close to a precision device. Read that sucker right below the thermostat housing, scan around the intake, look for max temp in that immediate area. It should be very close to your thermostat rating, within a couple degrees at most.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-12-18 06:56 PM - Post#2730828    
    In response to someotherguy

Have not. It runs a few digits to the left of 210. If 210 is 12 o'clock. Maybe 11. Where it used to run a few above 100. This whole thing is like day and night. One day everything is consistent with the first few years of ownership. New radiator and I get water noise and higher temp. I thank everybody but I can't believe that with the change of a radiator I get defective temp gauge and intake gaskets. Hard to believe. I'll try and hunt up an infra ray temp gun.



 
454cid 
Valued Contributor
Posts: 2666
454cid
Age: 45
Loc: West Michigan
Reg: 02-18-12
04-12-18 10:37 PM - Post#2730836    
    In response to Blueseasons

  • Blueseasons Said:
Have not. It runs a few digits to the left of 210. If 210 is 12 o'clock. Maybe 11. Where it used to run a few above 100.



That sounds like it's normal now, and it was showing low previously.

  • Quote:
...I can't believe that with the change of a radiator I get defective temp gauge and intake gaskets. Hard to believe.



Well, it doesn't have to be the intake, it could be the water pump, or a hose, or even a crack in the radiator that is opening up when hot. It could be a cascade of things too. A few years ago, I had my oil cooler lines leaking. The oil filter adapter also needed an new o-ring. I fixed both of those two things thinking I had the Exxon Valdez all squared away... nope, the hydroboost unit started leaking a day or two later, so I was still hiding from the EPA and Greenpeace.

99 K3500 RCLB


Edited by 454cid on 04-12-18 10:37 PM. Reason for edit: No reason given.

 
Skribble93 
Infrequent Contributer
Posts: 19

Reg: 02-03-18
04-14-18 05:20 AM - Post#2730931    
    In response to 454cid

Agreed it doesn't sound like an intake leak or something major more so small. I did the same swap from the quick connect to the old style nipple on my 93 350 when I replaced the motor (lost parts to the quick connect had the nipple on hand lol)and it has never given me a problem. Before losing the trans cooler I did however lose coolant slowly but never could find the issue until flushing the motor I noticed the water pump gasket had a very slight weep but always would burn off before it dripped down far enough to see while running. Changed the pump being it was gummed up from the coolant/trans fluid mix and new rad now no loss of coolant at all. Always check for the small things that normally you would over look.

If it's to loud your to old

93 K1500 Z71 step side 5.7 shorty headers and 2 1/2in straight pipes. 3in body lift and leveling kit.


89 K1500 4.3 rotted frame dubbed parts rig


 
Blueseasons 
Contributor
Posts: 102

Reg: 10-13-11
04-16-18 07:13 PM - Post#2731222    
    In response to 454cid

If thats normal. then I am good. Not sure where that water slosh sound is coming from. I can't image a hose connection swap is going to make any difference in anything. In an update. I turned it off on Sunday after driving to the gym and it would not start again. I don't think i'm getting spark. I ran across the street to the ZONE and grabbed a can of starting fluid. It didn't help and the other thing I noticed is my radio presets are gone. So I have bigger things to deal with now. Once I get it running again, i'll get the coolant changed, flush the block and see what happens with this other issue.



 
Gmctrucks 
Infrequent Contributer
Posts: 24

Reg: 03-15-17
04-22-18 01:49 PM - Post#2731880    
    In response to Blueseasons

Install a mechanical temperature gauge hey guys what about having the wrong radiator cap.



 
454cid 
Valued Contributor
Posts: 2666
454cid
Age: 45
Loc: West Michigan
Reg: 02-18-12
04-22-18 03:27 PM - Post#2731888    
    In response to Gmctrucks

  • Gmctrucks Said:
Install a mechanical temperature gauge hey guys what about having the wrong radiator cap.



I had a cheap cap that wasn't working for me, at one point, but I don't recall exactly what it was doing.


99 K3500 RCLB


 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

251 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.215 seconds.   Total Queries: 16   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 11:00 AM
Top