# Radiator Problems on Honda Civic **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [June 7, 2007, 4:47pm UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344 "2007-06-07T16:47:53Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![kidkayt](https://avatars.discourse-cdn.com/v4/letter/k/51bf81/32.png) [@kidkayt](https://community.cartalk.com/u/kidkayt)\ **Post date:** [June 7, 2007, 4:47pm UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/1 "2007-06-07T16:47:53Z")
I live in Colorado. Two part question - [1] This winter I noticed that the radiator would spray / eject fluid out of an area near the cap / reservoir, especially after an overnight freeze. I can’t find the leak but it always happened after I drove the car around a bit. i.e. it did not happen if the car was stationary. I tried revving the engine, etc - nothing. [2] Now in the summer I am noticing that the fluid level in the radiator drops, the coolant reservoir gets filled by a backflush, and the engine overheats. Any suggestions? THANKS MUCH FELLOW CT Folks ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [June 7, 2007, 5:47pm UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/2 "2007-06-07T17:47:36Z")
Well I would guess the first thing to do is to find that leak. Since you don’t seem to be able to find it, then it is time to bring in a local professional who likely will pressure test it. Keep in mind it may have an a head gasket or other issue. Winter or summer, it is a poor idea to hold off on this kind of problem as it will never become less expensive and can become a lot more expensive very quickly. ---
**Author:** ![kidkayt](https://avatars.discourse-cdn.com/v4/letter/k/51bf81/32.png) [@kidkayt](https://community.cartalk.com/u/kidkayt)\ **Post date:** [June 7, 2007, 6:41pm UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/3 "2007-06-07T18:41:05Z")
The oil is always clean and no sign of steamy exhaust. This seems like it is the radiator - a two year old Modine but has quite a lot of moldy like “stuff” at least as far as I can see after removing the rad cap. ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [June 7, 2007, 9:45pm UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/4 "2007-06-07T21:45:26Z")
Most likely a bad radiator cap. The cap regulates the pressure within the cooling system, and excess pressure is released into the overflow bottle. However, if the cap goes bad, it will release pressure (and coolant) at lower and lower pressures than originally designed, resulting in fluid loss and overheating. It could also mean a leaking head gasket, that is sending combustion gasses into the cooling system and over-pressurizing the system, but, then, you’d acutally see bubbles streaming through the overflow bottle. But, i felt I needed to tell you. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [June 8, 2007, 12:26am UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/5 "2007-06-08T00:26:04Z")
Is this two year old Modine an all copper and brass radiator or a plastic and aluminum one like the original? If its not like the original, I’d recommend that you replace it with a plastic and aluminum OEM radiator post haste. ---
**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\ **Post date:** [June 8, 2007, 1:43am UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/6 "2007-06-08T01:43:28Z")
It is painted black and appears to have plastic tanks; perhaps and Al body. I really don’t see any coolant leaks. Just a lot of “rust” in the fins. ---
**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\ **Post date:** [June 8, 2007, 1:47am UTC](https://community.cartalk.com/t/radiator-problems-on-honda-civic/344/7 "2007-06-08T01:47:56Z")
I should mention I picked up some Prestone Radiator Clean and will try this first to see if I can get the liquid to flow freely. I’m also thinking of putting a T-joint in the heater core path to flush the system out. These will be my first try at a remedy.