Hello I'm about to do a cooling system flush and radiator change on my 2003 Sierra 5.3 1500 "T" engine. I was wondering if I could use the HOAT blue Mitsubishi coolant instead of the dexcool. A friend of mine works in a dealership, and he offered a pretty good price on them, and I've been asking around about it and most said that this coolant is the best when it comes to additives. But I'm skeptical about using a totally different coolant in a Chevy, as most people I know use either the orange dexcool or the green stuff. That, and a lot of people hate on dexcool for some reason. What do you guys think?
That's the thing that I'm not sure about. The truck is my brother's, and he told me that he swapped to e-fans because "the old radiator and fan weren't cooling enough". Presumably because the radiator was small and it's hot af here, but if what he's saying is true, then he did have overheating issues. All my problems started after I flushed the rad and changed the brake booster (same day). I found out the brakes were clamping on much later, so I added spacers between the brake booster and the master cylinder so the brakes loosened up. I don't know if the brakes are still partially clamping on, but they're no way near what they were before adding the spacers.
But before I changed the coolant type I thoroughly flushed the old coolant out with a water pumping machine at a shop. I'm pretty sure the coolant types did not mix.
FWIW, when the tank cap is off and the engine is at op temp, I can see these small bubbles in the tank, and sometimes a bigger bubble comes out. But I've been running the truck for over half an hour and the bubbles don't ever actually go away. Plus, no head gasket leak since I've tested it with a combustion gases tester.
The air dam seems to be on. At this point the most likely scenario is either that the radiator was somehow f-ed up during the flushing or that there is still some air trapped in the engine block Before I change the radiator, which is the only thing that hasn't been changed so far, how do I 100% make sure that there is no air in the engine? I'm currently running it with the cap off, but I've heard there's a certain hose that needs to be unplugged until coolant comes out of it. I don't mind spilling some coolant since I have a spare gallon.
At first I didn't, until I used the cruise control and the car constantly downshifted to get up to speed, and noticed that I can't go faster than 50mph. All gears are fine, and the rpm sits on 2000ish while going 60.
The problem is, it runs perfectly fine inside the city and while idling. The only problem I have right now is the fans coming on high while driving +50mph. And they don't turn off AT ALL. And reading the temp with an OBD adapter, it seems that the faster I'm going the hotter it gets. I don't think the truck should run hot enough on the highway to turn the fans on high. Everything else is fine until I get on the highway or just high speeds in general, in which the fans never want to turn off.
Oil and filter were changed two days ago. 6qt of 5W30 fully synthetic. Heck, even the old oil seemed to still have some life. I never neglect oil and filter changes. Oil pressure seems fine to me. Increases with acceleration, decreases with idling. Head gasket leaks were checked with a combustion gases tester. It turned out negative. I wouldn't really want to try a motor flush, but I'm thinking about Seafoam. It helped BIG TIME in my '04 LS1 GTO.
Wouldn't the oil pressure drop if I had an oil pump related problem? I'm sure that my oil pump is working just fine because the gauge (I know, not very reliable) moves in it's proper range. And I did change the oil and filter two days ago, which looked fine to me. Fan temp is controlled through the ECM. It's the Nelson Performance fan harness.
The fans are blowing in the right direction (towards the engine). I didn't think of the temp gun before, but I'll keep it in mind if all else failed. How will checking the oil pressure switch help? I'm not really knowledgeable in this area. The heater core was bypassed, and the radiator and the coolant were taken out and cleaned again, but to no avail. The temps are within the safe limits indeed, but the problem is that they make my fans run all the times, and run on high even on the highway, and the faster I go the hotter the temps get. In the previous post I attached a video and said what's happening with the truck now. I'm actually beginning to think that the head gasket is "starting" to go out, that's why I ordered a combustion gases tester that's arriving tomorrow.
I did run the engine with cap off, heck, I even got it here on video the moment the thermostat opened. The coolant's level increased and it burped air out until the coolant dropped down again. And I did that a couple of times now. In the end I did replace the water pump btw, but to no avail. Although I found out that the old one was already making noise when I got it out, so it wasn't for nothing. I actually found out that the brakes were dragging because I replaced the brake booster and it seemed to clamp down on the calipers. After using spacers between the brake booster and master cylinder the brakes no longer drag and runs cooler, but it STILL runs hot (I'm relying on an OBD2 adapter to read the temp). I've noticed that the faster I go, the hotter the temp gets, and yes, it gets hot enough on the highway that the fans kick on high while driving +50 mph. And when I stop beside the road and shift to neutral, I step on the gas till it gets 2000-2500 rpm for 30 secs or so, and the truck gets cooler ALMOST INSTANTLY!. Here are screenshots of the coolant temp dropping on my phone while my foot is on the gas on two different occasions. I honestly found about this coincidentally.
So I'll make this topic as detailed and informative as I possibly can because I'm running out of options here. Video of the issue is included. I did a coolant and radiator flush on my '03 Sierra 5.3 to change the coolant from green ACDelco to orange Prestone. All the old coolant was flushed out of the engine and in with the new. The radiator was bled properly. After driving around for a while, I noticed my temp gauge starting to rise just above midway on the highway, and I can hear the fans kicking on high (did an electric fans swap). I didn't think much of it, but then it refused to cool down even though both the fans and the outside air are blasting through the radiator, and I know that the radiator is clean because there was no corrosion on the inside or outer debris blocking the airflow. I took it back to the shop, reflushed it, bought a new OEM thermostat, nothing helped. As a last resort, I did the following things to make sure everything is working correctly, and I'll mention some notes: *Thermostat has been replaced *Coolant was changed back to green 50/50 ACDelco, which faired a bit better than the orange Prestone. *Changed the temp sensor and its wiring *Bought a new fan harness from Nelson Performance because the old one got busted from how long the fans were running on high. *Radiator hoses were inspected, nothing is cracked or kinked. *Oil is not milky, nor getting smoke from the exhaust, and I'm not losing coolant, so no head gasket issues. *Car was running fine before the flush. *The car isn't drastically overheating, but there's no reason for the temperature to rise on or above midway when I'm cruising down the highway, and this will make the fans and the harness run harder. *This only happens after I push on the gas or the engine is underload such as cruising on the highway. *Sometimes when the car is idling, it takes awhile for the low fans to turn off, as in, it is cooling down slower than usual. The only two things that are left to suspect are the water pump (not leaking or making noise though), and that there is an air pocket trapped in the engine, and I'd appreciate if someone tells me how to check if there is one. If this behavior is normal, which I'm sure it isn't, please let me know. Here's the video. When the temp begins to rise I'm cruising around 55mph, and only cooled down when I came to a stop and slowly took off again. https://youtu.be/J5jeolKdtc8
Well I bought a new wire with a pigtail that I'll install tomorrow, and I'll see if that fixes my problem. Whenever I need to push on the gas, or the car has to go up a hill or downshift, the gauge goes above midway, and I can hear the fans kicking on high but then turn off after a minute. And then the car gets seriously hot and lose all its power. The car behaves normal in traffic or idling, but whenever I'm seriously driving it the temp suddenly increases, fans go on high then turn off, and then the car gets seriously hot because the damn fans are off. One thing I noticed is that when the fans turned off while it was still above midway, I fiddled with the lousy temp wire, and then the temp gauge suddenly decreased without the fans even coming on. I'm no coolant expert, but I don't think coolant can become colder suddenly in a running car with no fans.
No I did not lose coolant before, and no, there's no white smoke or milky oil. I've had mild overheating problems with the green coolant, but nothing that stopped me from driving the truck. I've posted a picture of the wire above, do you say it could cause all of the problems I'm having? I can see some exposure near where the wire meets the plug.
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