Coolant reservoir
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10th Gear
Joined: Nov 2015
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Coolant reservoir
Few days ago as I was checking the fluid levels in the TL-S I noticed some coolant spray over the engine cover. Looked around for the source and seen the reservoir cap was wet. Opened up the radiator cap and reservoir caps to top it off.
Revved the engine to get it up to temp and found the reservoir boiling over and seeping through the cap. Not supposed to do that. What’s causing this my fellow TLers?
Revved the engine to get it up to temp and found the reservoir boiling over and seeping through the cap. Not supposed to do that. What’s causing this my fellow TLers?
Instructor
Joined: Nov 2016
Posts: 214
Likes: 28
Sounds like its either too full, cracked rad hose, overheating or, you may have a bad head gasket causing air to force through the coolant system and flushing out coolant. Check for broken hoses by obviously looking for leaks then, lets test the head gasket. Start the car with the radiator cap off and give it a couple of low revs, if coolant blows out of the radiator, you're in need of a head gasket repair. At that cost, just source a used engine lol.. If that doesn't happen, lets try burping the system of all air. Start the car with the cap off again and the heater turned on full blast at 90 degrees. Add coolant as it sinks down until it gets to operating temperature and/or it wont take anymore. If it still overheats/ blows coolant over the engine bay, I don't know what to tell ya lol.
Pro
Joined: Sep 2014
Posts: 743
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If you had the thermostat changed recently, it's possible that it was installed upside down. There is a hole in the thermostat that is supposed to be installed upward so that air can exit the system. Also, as Kris said if the coolant is changed and the heater isn't opened up then you can have air trapped in the system. Also don't discount a bad radiator cap.
Check your oil and make sure it's clean and doesn't have coolant in it (frothy/bubbly and/or white/gray). If it has coolant in it then take it home or to a mechanic and stop driving it immediately.
Check your oil and make sure it's clean and doesn't have coolant in it (frothy/bubbly and/or white/gray). If it has coolant in it then take it home or to a mechanic and stop driving it immediately.
Thread Starter
10th Gear
Joined: Nov 2015
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Thanks for the replies Kris and Chojun. I just replaced both reservoir and radiator caps and still the same outcome. I’ll try the test you mentioned with rad cap off and starting the engine and burp the system as well. My next move will be checking/replacing the thermostat. Hope that would do it.
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10th Gear
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Update
So here’s an update to my coolant reservoir. Changed both reservoir and radiator caps to no avail. Changed out the thermostat but problem persists. Checked motor oil periodically for any water contamination but none seen. Hoses seem fine but maybe I should just change them out as well. Is it safe to say(rather not barring any other solution) that the head gasket would be the ultimate culprit. If so, how hard would it be for the diy like me? I’m no expert to say the least but I feel confident in trying to fix it. Or is there anything else I could try before undertaking a head gasket replacement? Could a flush(wishful thinking) be an answer?
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10th Gear
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Small crack!!!
Ok I think I found the problem. While I was running the engine for a few minutes in the late afternoon, right moment right time, sunlight ran across the engine bay and low and behold I see at the top of the radiator just an inch below the cap was a crack about 2 in long. A tiny little slither of a crack that could possibly wreak havoc on the cooling system. So now onto replacing that radiator. Anything I should know? Keep you posted!!
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10th Gear
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Ok so the new radiator is in. Took a couple hours to install but it’s in. Poured coolant and did the burping process. Seemed fine. Test drove it around for 10/15 minutes, gauge needle stayed lower than half at that point so I thought problem solved. Drove it to work the next day and when I got there, got out to the smell of coolant. Thought no way?!? Opened up the hood and coolant spray all over the engine again. Still coming from reservoir tank as evidenced by coolant bubbling as before. Air is still getting in. So my thought process is the head gasket. At that price, way to much to invest for a 16 year old car. I’m at a loss!!!
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10th Gear
Joined: Nov 2015
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Water pump?
Hi guys checking in again. Question, could a faulty water pump be subject to my problem with this situation. I’m guessing the pump isn’t working therefore it’s not circulating the coolant and the coolant is “stuck” between radiator and expansion tank. Yay or nay??
USAF Veteran
Joined: Jul 2018
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From: Socal CA
First, what did you coolant look like when you drained it? Was it brown/muddy looking or still pretty fresh?
Take a look at your radiator cap. Did you buy a new one with the rad or use your old one? The cap maintains pressure in your cooling system and helps raise the boiling point. A bad cap can cause coolant to blow back into the overflow tank.
You should consider doing a pressure test of the cooling system. This will tell you if you have a leak somewhere. Basically you pressurize the system using a hand pump and watch for a pressure drop.
Take a look at your radiator cap. Did you buy a new one with the rad or use your old one? The cap maintains pressure in your cooling system and helps raise the boiling point. A bad cap can cause coolant to blow back into the overflow tank.
You should consider doing a pressure test of the cooling system. This will tell you if you have a leak somewhere. Basically you pressurize the system using a hand pump and watch for a pressure drop.
3rd Gear
Joined: Aug 2019
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When you replaced the reservoir cap, did you check to make sure it had the little round rubber sealant? I am having coolant issues right now with my reservoir tank and I think it's because of this but I'm not 100% sure either. I posted a thread on it (06 TL coolant reservoir) hoping to get some answers!
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