Why does my car overheat after getting off the freeway

Tiny
KICKJON1985
  • MEMBER
  • 1998 HONDA CIVIC
  • 179,000 MILES
Recently, about a month ago I replaced the radiator in my civic because the radiator had a hole that had started to spew coolant. Other than the leak of coolant the system worked fine no problems with overheating at all. After replacing the radiator the system started heating up (not overheating completely but close once), but only when getting off the freeway. I have replaced the radiator cap, the upper and lower hoses, the thermostat, the clamps on the upper and lower hoses from jesus christ clamps to regular kind, and still heating up. Now during normal in city driving it doesnt heat up like that at all only after being at high rpms. Someone told me a blow head gasket but I have never overheated the car and and it worked fine before I replaced the radiator(of course for the leak). Any ideas?
Monday, June 25th, 2012 AT 1:00 AM

78 Replies

Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
I have bled the system and it is doing the same thing still. I parked it with the nose up hill and ran the car with the radiator cap off till the thermostat opened and saw coolant flowing, and kept refilling till it didn't need it any more.
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Monday, June 25th, 2012 AT 1:35 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Okay, now you chemical and pressure test it here are some guides to help you.

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/car-is-leaking-coolant

Please let us know

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Monday, June 25th, 2012 AT 2:15 AM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
What kinda chemical testing? Kw? Ph? I will buy a cap and system pressure test kit tomorrow
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Monday, June 25th, 2012 AT 2:18 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Its a bloc check-chemical tester that changes from blue to yellow in color if there's combustion leaking into the cooling system
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Monday, June 25th, 2012 AT 2:43 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Are you getting any coolant losses at radiator and/or recovery tank?
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Monday, June 25th, 2012 AT 8:42 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
Currently no. When the engine heats up it will drop some cause of the engine overheating but not normally.
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Monday, June 25th, 2012 AT 11:24 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
No coolant losses indicates the problem lies with the cooling efficiency rather than anything else. Are the cooling fans working correctly? Is this an automatic or manual transmission?
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Tuesday, June 26th, 2012 AT 1:42 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
Fan is working. It is an automatic transmission.
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Tuesday, June 26th, 2012 AT 2:37 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Does both fans work together? Was any repairs done on them previously?

At highway speed are there any indication of overheating?

Is the replaced radiator OEM, new or used?
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Tuesday, June 26th, 2012 AT 2:47 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
It ussually does t show signs of over heating at highway speeds. After I get off the highway it will start heating up. Ussually after I get back up to highway speed it cools down, but over the weekend I drove it on the highway, it cooled down after getting back on the freeway but after 5 to 10 miles it warmed up above normal while I was on the freeway.

The radiator is a new one from autozone.
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Tuesday, June 26th, 2012 AT 4:00 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
The 98 honda civic only has one cooling fan for the radiator. The other fan is for the airconditioner.
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Tuesday, June 26th, 2012 AT 4:01 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
For automatic transmission, they work together.

Have you rechecked the coolant level in the radiator and recovery tank? Do it with cold engine
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Wednesday, June 27th, 2012 AT 1:51 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
I did it this morning before I went anywhere. The radiator was full. The recovery was a bit low but I had to go on the freeway a couple days ago and it almost overheated so the radiator was low so it had been sucking it back in the radiator. But the radiator was full this morning.
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Wednesday, June 27th, 2012 AT 5:52 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
As for the fan issue, the 1.6 litre engine has the radiator and the condensor seporated. The radiator is on the left and the condensor is on the right. The oil cooler is part of the radiator. This being said, the fan conected to the condensor doesnt run while the one for the radiator does. I have attached a picture from the mechanic book I have of the engine I have. #12 in the picture is the radiator and the condensor is on the right of it under the silver bracket.
Image (Click to make bigger)
Thumb
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Wednesday, June 27th, 2012 AT 6:07 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
The system we have over here is different. For manual transmission, the radiator would be as you have in your vehicle but for auto transmission, the radiator spans the entire front and the fans works together.

If the radiator is sucking in the coolant from the recovery tank, that could indicate 2 things.
1. There was air in system and and has since self bled. You would need to monitor and see if the overheating occurs again.

2. There is a leak somewhere and it is using up coolant.

Top up the coolant and monitor the situation for another one or 2 times and aleways note the recovery tank level.

When you performed bleeding of the cooling system, did you turn the heater on?
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Wednesday, June 27th, 2012 AT 8:36 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
I think that the reason for the coolant level being low is cause the engine got close to over heating the last time I got off the freeway and spewed all the coolant out of the recovery tank on the ground by means of over flowing it. Since then I have filled the radiator, and have been filling the recovery tank slowly to completely fill the system. I have not yet had time, or the money to buy the equipment to pressure test or chemical test the coolant system yet either. One would think that it would be something simple as it worked fine before I changed the radiator. The fan seems to run, but I am curious if its working properly all the time? Is there a way to test this? Or just replace the relay and go from there?
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Thursday, June 28th, 2012 AT 2:07 AM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
When I got home today from work I poped the hood and checked to see if the fan was working and it seems to be working as it should. The thermostat would close, the fan will come on, then after the fan shuts off the thermostat opens. I checked this by feeling the pressure and temperature of the upper and lower radiator hoses.
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Thursday, June 28th, 2012 AT 4:44 AM
Tiny
KHLOW2008
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Did the engine seem to overheat during this trip?
Is the coolant level correct?
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Thursday, June 28th, 2012 AT 8:31 PM
Tiny
KICKJON1985
  • MEMBER
  • 41 POSTS
No it didnt, but it seems to be the lenght of the trip on the freeway. The coolant level wasnt low before I left work, but this morning, the coolant recovery tank was low. But I ran it with the heater on to see if maybe it did still have a bubble.
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Thursday, June 28th, 2012 AT 9:18 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Seems there could still be some air trapped in the heater system and as overheating did not occur, you would need to monitor the situation further.
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Thursday, June 28th, 2012 AT 9:23 PM

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